10th Anniversary Stream

The world
is as big as you want it to be.
Where will you go next?

Asriel, 10th Anniversary Stream end card

The UNDERTALE 10th Anniversary Stream was a two-day charity/auction livestream event for Undertale's 10th Anniversary, with donations going to Doctors Without Borders. A total of $361,407.76 was raised, and the event offered incentives and auctions.

It was revealed via the official Newsletter and from Toby Fox's social media. In the FALL 2025 Newsletter, Toby describes the stream as being similar to the 6th Anniversary Stream for Deltarune's Chapter 1. This alludes to Toby's text-to-speech, development commentary, along with the game featuring numerous alterations, including new NPCs and a soundtrack. During day 1, there were also live-action segments.

History

Planning for the event was considered years ago, but began back in late 2024.

On July 25, 2025, Toby made a social media post asking the fanbase for memories, and shared a link leading to creating a memory on the official Undertale website. It depicted an Echo Flower, and had the option to create a custom talksprite icon. A total of over 400,000 entries were submitted.

During playtesting, Toby stated it took over 8 hours to complete the playthrough. Due to Toby becoming sick prior to the announcement, a button was implemented for the stream to display when he was "poisoned" to indicate when he drew a mental blank, depicting the Annoying Dog being green.

Prior to the event, he also asked via a Twitter post on what the fallen human's name should be. The two viable selected names were Togore and Chara. While Gaster and Frisk had significant fan backing, they were considered nonviable due to their "special effects" not working with the system. The name could change between Chara and Togore at any SAVE Point based on which name had more money donated towards it during the charity battle. Togore was the most popular option on Twitter, but the charity battle's initial results caused the playthrough to begin with the name set to Chara.

The leading name changed several times over the course of the stream, with Togore being the name active for the first in-dialogue use of the fallen human's name in Waterfall. Chara would once again take the lead during the True Lab, when votes for the name were cut off, and went on to be the name used for the rest of the game. There was also a brief period of time where the name was set to Nubert. Several times during the second day of the event, Toby encouraged viewers to donate for Chara, or Charlie stalled while playing.

Credits

Many of the stream contributors are acknowledged via the Day 2 stream credits. It is sorted roughly in a similar order as the end credits for the stream, including guest contributors.

Sans in his "Dr. Jogboy" attire.

It was directed by Toby Fox, who was also responsible for some music arrangements, new character and area designs, Sans's "Dr. Jogboy" outfit, and the laughing walls in True Lab. However, he did not create actual sprite art for the stream.

The stream was hosted by the three "Fangamer Dads":

• Reid Young, the executive producer and part of the Fangamer Stream Team, who played with the Giant Toriel Plush during the stream and opens the door for 3D Toriel.
• Dan Moore, who briefly wears a commemorative Nubert tie, and interacts with the Annoying Dog during the stream, such as petting.
• Charlie Verdin, who was the primary player for the playthrough.

Programming for the Undertale build for the stream was performed by "The Three Musketeers":

• BeholdMaxine: one of the directors and writers for TS!Underswap, as well as the creator of RIBBIT, a mod for Deltarune. BeholdMaxine's largest contributions include the school sequence, bed lump, Dog Hole, and Spamton's scene. Her happiest memory is of Toby retaining the dialogue and door sprite gag for the scene in Undyne's house.
• Spasco: a lead programmer for Undertale Yellow.
• colinator27: a musician and lead programmer, also for TS!Underswap.

All the Three Musketeers are also credited for new programming for the 10th anniversary battles hosted on the official Undertale website. Additional programming was done by Fred Wood, and he is credited for contributing to the pacifist battle versus Sans for the "Ask Sans To Go All Out" incentive.

One of the stream logos animated by Smallbu.

Temmie Chang contributed as the main artist. Other contributing artists include Kenju, who created the Hotland buildings, and Merrigo, who created the Waterfall underwater parallax background. Smallbu Animation, who has created animations in Deltarune such as Tenna's introduction cinematic and Kris playing the piano, has created multiple versions of the animated 10th Anniversary logo for the stream.

Camellia created the Wrong Number Remix upon Toby's request, which is further elaborated on in the description for the remix's video. Carlos Eiene, who has made the Live at Grillby's album, is credited for the music arrangement of the Song That Plays When Somebody Verses Sans track, as well as Snowed Inn Jazz and what's up?. Marcy Nabors, who has also helped compose Deltarune's Attack of the Killer Queen, did MIDI transcription for the Abandoned Town and Underwater Town tracks. The intended credits for the intermission music were not functioning during the first day of the stream, but Toby credited them as fanmusic from the UNDERVEIL project and arrangements from Carlos Eiene. See also: intermission tracks for the full tracks and credits list.

Robert Sephazon was the producer, and conceptualized the Memories project with Fangamer. Brian Coia, part of the Fangamer Stream Team, assisted on stream and website tech and the Memories project. Brian synced the text-to-speech with the Annoying Dog plush's mouth, and recreated the Echo Flowers room that is used for the Memories pre-stream/intermissions.

wayneradiotv, part of the Fangamer Stage Team, reprised his role as Spamton A. Spamton from the Fangamer livestreams. Wayne was also a camera operator the entire time while in his Spamton A. Spamton attire. Señor Romero Piñatas created the 7ft tall 3D Toriel piñata that appears during a live-action segment. She was made from newspaper, water, flour, and cardboard, and was the largest piñata Señor Romero Piñatas has made as of September 20, 2025.

The Fangamer staff also includes:

• Stream Team: Everdraed as the creative lead, who had been part of the planning for the event for years. He at some point drew a different version of the logo with a concert piano at a different angle, though it exposed the "ultra realistic piano-playing hands". Everdraed appears on the set on the second day, acknowledges Omega Flowey's name, expresses his thoughts on the battle, and his experience with the Undertale Demo. Nathan Cranford is credited a project manager.
• Stage Team: Steve Campos as the director, Mike Stimpson as another camera operator, Brittney Olsen and Aaron Cargile as producers, and Dylan Browne for audio tech.
• Design Team: Eyes5 as the plush designer, Camille Young as the diorama designer, and for Fangamer support is Chess and the Fangamer Volunteer Mod Team.
• Art Team: Sara Luu, Lorenzo Vissichelli, Danny Picou, Danny McGee, Morgan DiFede, Cass Robinson, Michael Ferguson, Angela Phelps, Derek Carmody, Marcos Rosas, Joelle Blot, Heidi Mandelin, and Audrey Waner, who made the final 10th Anniversary logo.

Special thanks was given to the UNDERTALE modding community, and the stream's viewer.

Development

Information revealed pertaining to Undertale's development, and some of Deltarune's.

Ruins

Several aspects of the Ruins were inspired by the game Brandish, including the area's name, its puzzles, and the plaques on the walls. The music of the Ruins was inspired by Secret of Mana.

Toriel's speech is intentionally written to avoid using contractions, which Toby describes as "her special super duper Homestuck typing quirk". Toriel's appearance was inspired by the Mimiga from Cave Story, which Toby said "everyone knows", including the creator of Cave Story, as Toby had personally told him. Toby also describes how Toriel was originally intended to have a more humanoid appearance and be "some kind of motherly goddess", noting that this idea was "too close to Breath of Fire 3".

Several of Undertale's characters were named based on results from a random English word generator website, including Napstablook and Asgore.

Ghost Fight was originally made for a compilation of Super Nintendo-styled music. As a fan of the game OFF, which includes a jazz-like song that plays while fighting ghost enemies, Toby felt that assigning a ghost character a jazz song would be a fitting combination. Toby does not think Napstablook as a character has anything to do with jazz, though.

Froggit was intentionally designed to have a confusing appearance, with it being ambiguous whether the second face is part of a single Froggit, or if it is a separate creature that hides under it.

Due to the existence of Flowey, plant-based monsters were usually avoided. The notable exception to this is Vegetoid, which Toby claims was included as he "was afraid the player wasn't going to get enough Vitamin A". He then says that Vegetoid is "technically not really a plant anyway", rather being a monster that looks like one, though he adds that this is how he personally sees it. Toby recalls that it was impossible to spare Vegetoid without attacking it in the game's demo, which he now realizes was "not great design".

Loox was the first enemy in the game to be designed by Temmie Chang.

A major motivation for the direction of Toriel's character was that Toby wanted to create a mother character "that was actually a character beyond being a mother". He cites his own dissatisfaction with the handling of a mother character in Mother 3 as inspiration for this. Later in the stream, Toby discusses how one of his friends criticized Toriel for being what they deemed a "perfect" character, as they did not feel she had flaws beyond being "too nice". This encouraged Toby to show more of Toriel's flaws over time, as he feels it is important for characters to have imperfections to give them depth.

Snowdin

The characters of Sans and Papyrus were inspired by Toby's friend J.N. Wiedle, also known as Jones, who loves skeleton characters. As Jones's webcomic Helvetica centers around a skeleton named after a font, Toby made skeletons named after "the most annoying fonts of all time" as a reference to said webcomic. Toby notes that at the time Undertale was being developed, expressing exaggerated hatred for the Comic Sans and Papyrus fonts was a popular meme, and that he finds it funny that this joke has lost popularity since the game came out.

Toby describes the fundamentals of his sense of humor as coming down to "two wacky guys". This approach goes as far back as when he was five years old, and would play pretend by making his left and right hand into different characters who acted as comedic foils to each other.

Sans using the ハッピールイカ (happī ruika, "HappyRuika") font in the Japanese version of Undertale.

At some point in the Japanese translation's development, Sans was intended to use the "Poptai" font (likely referring to Soei Kakupoptai) though this did not come to pass. Toby does not remember the actual font used in the final translation, which is the ハッピールイカ (happī ruika, "HappyRuika") typeface.

sans. was originally created for an early version of Deltarune, where it would have played in a gym in Card Castle where several Rudinns would be working out, with one saying that "the brain is the strongest muscle of all". According to Toby, this scene was intended as a reference to a gym in Space Funeral. This original context is presumably the reason the track is internally referred to as mus_muscle.

sans. was directly inspired by the song In and Out Crowd from Sesame Street. Toby explains that Kanotynes, the artist behind the designs that inspired Deltarune, is a fan of the work of animator Sally Cruikshank, which led Toby to watch all of Cruikshank's animations. Upon watching the In and Out Crowd animation, Toby decided to make a homage to the song to practice music. He says that he felt the reference was very obvious, and that he was surprised to never see it pointed out by the fanbase, though Reid's son apparently identified the similarity to Sesame Street immediately.

Toby states that the reason for the abundance of dogs in Undertale was Temmie liking dogs, and reveals that he actually prefers cats. Around the time of Undertale's development, Toby was "all about Pomeranians" due to Temmie having a pet Pomeranian named Kibble. He recounts a frequent joke of his where he would say he had concept art to send Temmie, and instead send her the same photo of a Pomeranian, and that eventually this joke turned into editing the Pomeranian to be longer. Toby believes this story is the reason that Lesser Dog was added to the game, but is uncertain as it had happened twelve years ago.

Toby seems to confirm that the Mettaton-like machine used by Papyrus to activate the Multicolor Tile Puzzle is, in fact, Mettaton himself. However, the on-screen captions show that he typed several question marks while saying so, which may indicate he is uncertain about this.

Temmie drew several more parts of The Gauntlet of Deadly Terror that were not used. Toby also says that the Annoying Dog dangling from a rope in said scene is his favorite graphic in the game.

Toby says that Snowdin Town is one of the only songs in the game that he is able to play on the piano and still have it sound good, though he does clarify that all the game's songs were initially composed on the piano.

Toby does not remember how he made the image used for the fog before Papyrus's boss battle, only that it was "something that got mirrored".

Toby reveals that Nyeh Heh Heh! was originally composed as Lancer's theme in a 2012 concept for Deltarune. He calls this "famous" information despite having never shared it before. He also repeats that Bonetrousle was originally made to be Deltarune's normal encounter theme, which he had already stated in several other sources before the stream.

Waterfall

Waterfall is the first area in the game to have tiles created by Kenju, who also created the tiles for Hotland.

Toby says that Loren's original concept, as thought of by Kickstarter backer Colin MacDougall, was that of "a guy that wants to eat everything", though he admits he does not remember the details of the concept well, joking that Loren ate his memories of the event.

Upon reaching the battle with the Mad Dummy, Toby mentions that he had wanted to include a consequence for the player's actions in the initial encounter with the Dummy from the very beginning, and says that it was fun to remix Ghost Fight to create Dummy!.

Toby shares some information about the grid background in encounters at Reid's request, stating that the original intent was for monsters to always be aligned to the grid, though Toby is unsure if he kept doing this in later areas. He also reveals that the grid's color was intended to change depending on the current area, as opposed to always being green as it is in the final game. Toby says that he planned to have this happen in Deltarune as well, but once again forgot to include it.

Some of Napstablook's traits were inspired by a friend Toby had in college, who he has not spoken to for many years since. Toby says he does not know if that friend liked being "part of the Napstablook recipe", but he hopes that he does, since "otherwise it would be really weird".

In Temmie Village, Toby states that Temmie's speaking style was inspired by how Temmie Chang used to type at the time of Undertale's development, which was previously shared in an interview with Temmie from the ISSUE 2 - Spring 2023 Newsletter. He states that Chang has since stopped typing this way, saying that he searched his chat history with her over the past 4 years and there were no results for "hoi", which she once said often. He recounts that Chang had mixed feelings about being heavily associated with the Temmie character from Undertale.

Toby describes that while he wanted Undertale's characters to feel like real people and put great effort into conveying their personalities, he has created each character with a specific purpose in the game's narrative. He then explains the primary intent behind certain main characters: Flowey was created to introduce the game's conflict of violence versus mercy, Toriel was made to test the player's trust after being tricked by Flowey and demonstrate the impact of their choices, Papyrus is intended to be a character that is "nearly guaranteed to be your friend", and Undyne is supposed to be the first character that cannot be spared in the same way as the game's encounters up until that point. All of these characters present different ways of exploring the story through the game's mechanics, and each character evolved to have more depth past their initial role as he continued to write the story.

Reflecting on people asking him how he makes his characters, Toby states his belief that the most important element to making good characters is to make a story for them to have purpose in: "Purpose and function first, personality etc. later."

Toby repeats that he had not known what Undyne's personality would be until he began writing the cutscene immediately before her boss battle, saying that a large part of her characterization was made up last minute at that point. Undyne was at one point intended to have "some sort of serious British knight accent", which Toby compared to the character Frog from Chrono Trigger, and was intended to be a much more serious character than the rest of the cast. Toby expresses that he feels like it was for the better that Undyne's character ended up being "a little bit goofy".

スシの　ニオイがする。 (Sushi no nioi ga suru., "Smells like sushi.")

Toby requested that the "Smells like sushi." flavor text in the battle with Undyne be kept unchanged in the Japanese translation, despite the fact that the word "sushi" simply refers to vinegared rice in Japan, rather than the association with raw fish the term often has in English-speaking countries. He says that while it could have been changed to refer to something that would have maintained the connection with fish, such as sashimi, he considered the original line "too famous" to alter at the time. After explaining this, Toby repeatedly attempts to credit Keiko Fukuichi for the game's Japanese translation, which he does in Japanese; however, this can only be seen by translating the on-screen subtitles, since his text-to-speech program does not support the language and fails to read most of the sentence.

When designing the game's battle systems, Toby tried to choose mechanics that would be intuitive even if the player was unfamiliar with any given genre. He compares the green SOUL mode's mechanics to rhythm games, saying that it is "probably easy as pie" for those who are good at such games.

Hotland

Dog food drawn by Clairvoire.

By the time the game reached this point in development, Temmie was very busy with school, so much more artwork had to be created by Toby or other artists. Clairvoire drew the bag of dog food in Alphys's Lab, the outer facade of the MTT Resort, and the sprite for Mettaton EX's Happy Breaktime "attack". Toby drew many of the graphics in Alphys's lab, which he states to be the reason for any perceived faults in them.

Alphys's name in the Japanese translation is instead "アルフィー", or "Alfie", which was Toby's own suggestion. He says that he was not aware of the existence of the Japanese band The Alfee at the time, and expresses slight regret over this, as he wanted the names of his characters to be unique to make it easier to search for them.

Alphys's voicebyte is a clip of Xan Wetherall's voice. Xan would later become part of the development team of Deltarune's Chapter 2.

Mettaton was apparently included in the game in order to appeal to Toby's friends who are fans of Transformers. Toby also alludes to the concept of an "electric game show host" being inspired by the character of Bob Sparker from Tales from Electricopolis by Pauli Kohberger, as is stated in the game's end credits, though he does not name him or Tales from Electricopolis directly during the stream, and simply refers to "(his) friend Moon's character". Toby summarizes the intent behind Mettaton as "trying to make fanservice for Jones".

Alphys's main visual inspirations were John Egbert from Homestuck, Lisa Simpson, and "that lizard guy from Super Paper Mario", though Toby admits that he has never played said game.

The song Another Medium was originally composed for Homestuck, but was not used in the comic, leading Toby to repurpose it for Undertale.

Tsunderplane's hat is based on that of Yukari Yakumo from the Touhou Project series. The bug where Tsunderplane shrinks into the top-left corner upon being spared was intentionally left in the game, as Toby found it funny.

Several unused sprites of scrapped monster NPCs drawn by Cap are shown while the hosts trek through Hotland, including a "green radioactive fox" who would have skateboarded into the lava and died. This character was scrapped, and the Annoying Dog was invented as an avatar for Toby instead.

さつじんロボのキラキラキッチン (satsujin robo no kirakira kitchin, "Killer Robot's Sparkling Kitchen").

The Japanese version of the "Cooking with a Killer Robot" logo was drawn by Hato Moa, who is best known as the developer of the visual novel Hatoful Boyfriend and is one of Undertale's earliest Japanese fans. The English version was drawn by Toby himself.

Hotland was intended to have more robotic NPCs inhabiting it. However, it was decided that Mettaton being the only robot would be better for the story, as he would be more unique.

In addition to RG 01 and RG 02, who appear in-game, and the unused RG 03 and RG 04 who remain in the game files, an additional pair of Royal Guards was planned. Toby had thought of "insane evil situations" that would occur when the Royal Guards were killed, such as a situation where upon one enemy's death, the other would inhale their dust and have a panic attack as a result. A friend Toby told about this idea did not like it at all, leading him to scrap it. He believes this was for the best, as the concept was "too edgy".

Toby shared several early enemy ideas for Hotland, most of which went unused. The exceptions were Temmie, who instead appeared in Waterfall, and "Tsunder IV" and "JF-17 Tsunder", which appear to have been early names for Tsunderplane. One listed enemy, "Sweltering Snowman", would have been a reference to a fake EarthBound enemy invented as a joke by Reid Young in the early days of the Starmen.net forums.

Toby acknowledges that Muffet is considered by many to be one of the most difficult bosses in Undertale, and recalls nerfing her several times after the game's release. He also states that the "up next" sign for her attacks was inspired by The Arena from Kirby Super Star. The bullet board moving up and down during some of Muffet's attacks was accomplished by copy-and-pasting regions of the screen in a "very inefficient manner", which impacts the game's performance on older computers. The sprites for Muffet's pet were cleaned up by Chess.

The musical segment with Mettaton was originally going to have a system where Mettaton would have different dialogue reacting to the protagonist's behavior as he danced with them. The strings for this still exist in the game's files. Toby does not remember whether this idea was scrapped due to feeling "weird" or a bug resulting in the dialogue not showing up. The Xbox port of the game initially contained a glitch where this dialogue suddenly showed up, which greatly confused Toby, as there was no discernible reason in the code for this to happen.

It was once planned for the MTT Resort to contain a small area which would have been a "giant bed field", accessible via the elevator. The area itself would have contained monsters in cryostasis waiting for the barrier to be broken, several "bed lumps" and NPCs who would be sleeping or talking about their dreams. The background music for the area would have been slowed-down and reversed, along with an effect resembling falling snow. The intent of the area was to show to show how many people were waiting to be freed. Toby eventually decided he did not like the idea, so the concept was scrapped.

The resort was also planned to include an arcade area, where the protagonist would be able to play games while Monster Kid provided commentary. At one point, the protagonist was intended to play "Egyptian rat fink" with Sans, which may be another name for or variation of the card game Egyptian Ratscrew. This was cut due to being too difficult to program, though Toby implies that Sans's presence at the Dog Casino in the game's Xbox ports may have been in reference to this scrapped concept.

While writing Burgerpants's dialogue, Toby had no idea what dialogue to write for a shopkeeper, leading him to "let [his] own desperation take over". Toby acknowledges a now-patched bug where a placeholder message referencing The SpongeBob SquarePants Movie would appear if he was spoken to under certain conditions. Toby also describes the dialogue about the Nice Cream guy and Mettaton that was added in v1.001 to fix this bug as "fanservice".

The graphics for the bridge to the CORE were designed by Gigi D.G. and drawn by Chess, while the interior once again had tiles drawn by Kenju, and the area's concept art was drawn by Temmie. The CORE was originally planned to be a much larger and more difficult area, but after making five enemies, Toby decided that they would provide enough variety for the area.

It was once planned to be possible for the protagonist to "marry" Mettaton, similarly to being able to "date" Papyrus, which Toby recalls had previously been mentioned during the game's Kickstarter campaign. Mettaton would have accepted the proposal, but only as a fake photo op to promote himself in tabloids. Toby eventually lost interest in this idea and felt like it no longer fit in the game, so it was scrapped.

While the hosts proceed through the CORE, Toby shows a document containing a list of armors and weapons that he had thought of before coming up with a consistent theme for them. Some of the armors in the list include "Papyrus Armor", "Cyber Jammies", and "Asriel's Shirt". He also shows a screenshot of a document that simply includes a name and description for a "Wormostat" item, the intended purpose of which is unclear. A few minutes later, he shows alternate concepts for weapons and armor that were made after he had settled on the theme of the previous fallen humans. These concepts include a scout who would have been represented with hiking boots as a weapon and a merit badge as armor, and a naturalist whose items would have been a bug net as a weapon and a flower crown as armor. He also shares the script for a scrapped cutscene where Papyrus would call in to Mettaton's quiz show to help the protagonist.

While working on the boss battle with Mettaton EX, Toby was concerned about the level of difficulty. Because of this, he created a separate program that only contained the battle, which he gave to some of his friends to observe how many tries it took them to win. Toby considers Mettaton EX to have been the most difficult battle in the game to create in terms of attacks, as the yellow SOUL mode took more effort to think of new gameplay for than the other modes. On the other hand, Toby found creating the ACTs and point system fun to make, and enjoyed adding different ways to obtain points.

Mettaton EX's unused dialogue portraits, which show a more robotic-looking side of his face, were intended to be used after his defeat. Toby changed his mind about this, but the concept was repurposed for Mettaton NEO's design.

New Home

The track Undertale was inspired by the song REDLINE DAY from the movie REDLINE. Toby notes that the song's lyrics unintentionally align with the narrative themes of Undertale, quoting the lines "You are the flower, I'm the rain/Without you, life is not the same". Toby also cites the song Pneuma from the soundtrack of the live-action Solanin film as an inspiration for the track, saying it might have been a bigger inspiration than REDLINE DAY.

The starting melody of ASGORE was inspired by The Fog from the game Persona 4, to the point where one of Toby's project files that only contains the initial melody is called persona4.FLP. The version of ASGORE in the original project file is said to be "massively" faster than the in-game version; Toby deliberately sped up the track so that it would sound good when slowed down. The track Determination, and by extension its leitmotif that is present in ASGORE, was inspired by the Game Over music from Brandish.

The inspiration for the Game Over screen foreshadowing Asgore came from the game Final Fantasy Legend II, where the character Odin can revive the player's party if all characters are defeated in battle, in exchange for having to battle him at a later point in the game. Other inspirations for Asgore include the final boss of Brandish, who is also a king the player must defeat to leave that game's underground world, and Amon from Lufia 2, who inspired the design of Asgore's golden armor.

The battle with Asgore was designed to be difficult, but still possible for players unfamiliar with bullet hell games. In service of this, several features were implemented to make the battle easier. Asgore's attacks were made to always leave the protagonist at 1 HP if their HP is higher than 1, meaning that equipping the Stained Apron will always allow them to survive another hit after its HP recovery. There are also several means by which Asgore's defense can decrease, including the Butterscotch Pie and his defense dropping every turn after the twentieth turn. In addition, the Bisicle item was designed to be intentionally "super useful/broken" while playing through the True Pacifist Route.

Omega Flowey

During the battle against Omega Flowey, Everdraed appears on the stream to discuss his contributions. Everdraed describes the experience of putting Omega Flowey together as being "scary in itself", but also says that being able to contribute to the game was very meaningful to him.

Toby details how the point of the Omega Flowey battle is to make the player feel "overwhelmed and hopeless" at first, to the point where one might conclude that the battle is impossible and is indeed the end of the game. One technique used to achieve this was the HP decreasing by a disproportionate amount when the protagonist is hit at high HP, but with very little damage being taken when HP is low, giving the illusion of the attacks being unfair while ensuring it is still possible to win.

Toby implies that the human face that appears on Omega Flowey's TV screen is his own face, and explains that the high contrast monochrome effect was achieved through exploiting a bug in an early version of Christine Love's Super Game Girl Camera application where the image contrast could be set to a negative number, creating a strange effect.

Toby explains that due to the amount of large graphics in the battle, he worried that it would increase the compile time of the game project. Because of this, he created an entire separate project to program the boss in, which was incorporated into the rest of the Undertale game project upon completion. This is the reason for the game's files including duplicates of several basic assets.

Toby initially created the boss with placeholder graphics, and programmed a method for it to be possible to replace the graphics at runtime. This was done so that Everdraed could see his assets in the game immediately as he was working on them.

In the stream, Toby also takes this battle as an opportunity to talk about how he intentionally had some of Undertale's sounds in general use a low-quality version of the .wav format, expressing that the compression and distortion added character to the sounds, and that he feels it suits the aesthetics of his games to not sound entirely "clean". He also thinks it was fun to try to get the game to have a small file size.

At the time he made the assets for Omega Flowey, Everdraed had only seen the Ruins, having contacted Toby to ask if he wanted help after playing Undertale Demo. Due to this limited context, he was "blown away" by how different the experience of the full game had been from what he expected when he was working on Flowey's assets, and expresses pride at his work in the battle being the "punchline" of the game.

Toby confirms that the synth preset used for the lead instrument in Your Best Nightmare is "Pad - Freak Choir" from the "Ultimate Sytrus" preset pack for FL Studio, and expresses an interest in synth presets that are "useless for any sort of normal songs".

Notably, both Toby and Everdraed consistently refer to this form of Flowey as "Omega Flowey" during this section of the stream, arguably canonizing what has long been considered a fan name.

Toby implies that Sans's mandatory Cell Phone call at the end of the Neutral Route is inspired by the post-credit scene of Metal Gear Solid 2: Sons of Liberty. He also claims to have drawn inspiration for "meta elements" in Undertale's battles from the same game.

Additions

The build of Undertale played on the stream has several unique additions. According to Toby, these details will remain exclusive to the anniversary event, with their canonicity being left to the viewer's interpretation. Such changes include new locations, music, dialogue, and cameos or allusions to Deltarune:

General

• A "Naming" option was added in the SAVE Point menu for changing the name of the fallen human.

Ruins

The center of Home.

• The eastern Ruins balcony stretches further to the right than usual, ending at a set of stairs that descend into Home. The Delta Rune appears atop an entryway with its triangles inverted, similarly to its depiction on the windows in the Last Corridor. Opposite of the entryway are some buildings and a statue resembling Toriel at the center of the area. The Toy Knife is retrieved from a building with a mirror and a bookshelf.
• A mobile crib appears in Asriel's room in Toriel's Home. It spins when the light is turned off.
• In the epilogue, Gerson appears in the building that contains the Toy Knife and comments on The War of Humans and Monsters. A Froggit also appears near the aforementioned entryway and comments on the previous fallen humans.

Snowdin

Noelle, as seen in Snowdin Town.

• In Snowdin, a new area was added nearby the mysterious door via a descending tunnel going down. A Lumberjack NPC appears, who muses about staying in that area and mentions that Asgore has visited everywhere. This area can be exited via a lift in the shape of a dog, placing the protagonist just after the third XOXO puzzle.
  • In the epilogue, the Lumberjack has decided to put hats on the trees instead of cutting them down.
• A young Noelle can be seen behind the decorated tree at the center of Snowdin Town.
• The snoring guests found when renting a room in the Snowed Inn play saxophones instead of sleeping. The melody they play is the same as the one in "Determination".
• The phone call dialogue associated with the wrong number song was changed, and the song was replaced by Wrong Number Remix, by Camellia.
• Several community goals were held as incentives, with four of them, ranging from $25,000 to $230,000, being tied to Sans. All of these segments take place in an empty version of the Dog Shrine room, located beneath the tall sink in Papyrus and Sans's house.
  • $25,000: Unlocks "Verse Sans". After the protagonist defeats Papyrus, they can enter the empty Dog Shrine room during the hangout with him. Inside, they ask Sans to do a verse battle for charity. Though reluctant at first, Sans agrees and begins rapping about himself. Papyrus soon enters, asking if they are "SAYING VERSES", which Sans confirms and clarifies that his verses are only about himself. Papyrus joins in, sparking a playful rap battle between the two. The exchange revolves around Papyrus claiming his computer broke due to a "VIRUS". Sans suspects hacking or unusual subscribers, but Papyrus explains that his CPU "WENT ON STRIKE" after he posted a status confessing he dislikes anime, which he claims "INVITES AN INFANTILE WORLDVIEW". Sans warns that the computer may be under attack by a "nerdy stranger". When Papyrus asks what to do, Sans advises lowering his aggression and admitting that it was just a minor mistake. Papyrus realizes the "virus" was simply someone downvoting his post, later revealed to be a girl. He decides to make his post friends-only, leaving satisfied and ending the rap battle.
  • $80,000: Unlocks "Battle Sans". After the protagonist completes all of Mettaton's segments, they can return to the empty Dog Shrine room, tell Sans that another charity goal has been reached and ask him to battle them. Though admitting he is not much of a fighter and expects to lose, Sans agrees for charity's sake. He initiates an encounter, allowing the player to engage in a fight with him briefly before leaving the room, which forces the player to flee.
  • $200,000: Unlocks "Sans Attacks". After the protagonist reloads their SAVE file after defeating Omega Flowey, they can return to the empty Dog Shrine room once again. Upon hearing that another goal has been met, Sans is asked to initiate a fight himself. Surprised and doubtful that anyone would donate for such a thing, he nevertheless agrees for charity's sake, though only once. He initiates another encounter, this time letting the player experience a full battle against him.
  • $230,000: Unlocks "Ask Sans To Go All Out". During the True Pacifist Route epilogue, the protagonist can return to the empty Dog Shrine room one final time. Before they can speak, Sans guesses what they were going to ask. He admits that he appreciates the "charity stuff", but says that fighting is not really his thing. To him, concepts like "right" and "wrong" are not simply numbers to add or cancel out, though he acknowledges the protagonist's good intentions. Instead of fighting, he suggests doing something kind and offers a hug. If the protagonist accepts, they approach Sans, only to fall for his "ol' full-body" whoopee cushion trick. Papyrus then enters, asking about the noise. Sans explains it was the same prank he used earlier on the protagonist, which Papyrus deems "COOL", though only once. Papyrus leaves, and Sans follows him shortly after.
• Papyrus's "secret style" that he usually changes into during the hangout with him was completely redesigned. The T-shirt now reads "COOK DUDE" instead of "COOL DUDE", and the rest of Papyrus's appearance is more similar to that of a cook.
• While Spamton A. Spamton plays the game, Spamton replaces Sans during most of the conversation at Grillby's, changing a majority of the dialogue and events. Spamton also devours a 258 pixels-large fry. After the hosts came back, this character swap was reverted, albeit Sans's dialogue differed slightly at the end.
• After defeating Asriel, Glyde appears in front of the mysterious door, revealing that he had broken it open after 10 years. This negates the need to complete the True Pacifist ending credits without touching any names.

Dog Hole

Main article: Dog Hole

The first and only known room of the Dog Hole.

(10 years worth of dog hair has accumulated...)
(... forming a living labyrinth beyond understanding.)
(... the dungeon stretches on for hours before you...)
(You're filled with determination.)

SAVE Point at the beginning of Dog Hole the first time you interact with it

A new room added in Snowdin's mysterious door, which can be entered via a hole in the center of the room where the Annoying Dog originally slept. It is a "living labyrinth" of a decade worth of accumulated dog hair, and its sole SAVE Point reveals it has 100 floors.

However, it is not explored past the first room as the hosts decide it would take too long to go through for the purposes of the livestream. Abberant and Mr. Sunshine (the latter of whom is a cut enemy from Undertale's Hard Mode) are fought here, as well as two unnamed enemies encountered while leaving that are immediately fled from before any interactions are made. The assets refer to the latter two as "Vitamoid" and "Wintercoat".

Waterfall

The brown door in the fake hallway of Waterfall.

• The gray door leading to room_mysteryman in the fake hallway has been replaced by a brown door, which seems to resemble the door to Sans's room. The door is ignored by the hosts, and the hallway is absent when they return through the same area in the epilogue.
• The Punch Card obtained from buying Nice Cream from Nice Cream guy's stand has been altered. It displays a drawing of a smiling bunny alongside the text: "it's cool if you leave. probably."
• The linear path with Onionsan instead takes place in an underwater village with unique NPCs, and the protagonist traversing upside down in a bubble.
• The spiderweb in Napstablook's house was replaced with a fourth CD, which is labeled "Mettaton Voice Drama CD". The CD's contents are Mettaton repeatedly saying "OH YES!" at varying pitches and speeds.
• During the date with Undyne, before Papyrus leaves by breaking the window, Undyne requests that he use the door instead. Papyrus complies in his own way by opening the window as if it were a door, exiting through it. After Undyne tells the protagonist to leave her house, Papyrus reappears, instead spilling broken glass shards out of nowhere and crashing through the door upon re-entering Undyne's house, causing the protagonist to step aside.
• During the date with Alphys, Sans appears in a "Dr. Jogboy" outfit before Papyrus appears in his "Jogboy" outfit like in the regular game.
• The poster in Mettaton's house was extended to reach the left side of the house.

Hotland

Fire-E, Hotland High's extremely unpopular mascot.

• Hotland has several new background buildings, many of which are floating and hanging by chains. Hotland High is a new location, featuring new NPCs and cameos from Deltarune characters such as Milk Looker. A sequence involving the school took the place of the section immediately before the bomb defusal.
• During the bomb defusal minigame, the Script Bomb was changed out for a Mad Bomb, which used the sprite of Mad Mew Mew. Instead of having the option to defuse the bomb, the protagonist had to fuse Mad Mew Mew's head with her body.
• On the far-right platform of the last steam vent puzzle is a new NPC holding a camera, as a way to poke fun at the room's appearance in every trailer.
• In the MTT Resort, the protagonist can sleep in a wider bed than usual for 200G, and a different beat, Ultranap, plays while they move around the bed.

New Home

The path leading to New Home's "Nose-Nuzzling" stage.

• Before the Last Corridor, there is a new path next to the elevator. After the "Return to New Home" incentive was reached, the path is revealed to lead to a populated grayscale version of Home with a "Nose-Nuzzling" stage at the center. In the following order, the protagonist can get nuzzled by Toriel, Papyrus, Undyne, and Monster Kid.

True Lab

• When the shower curtains are pushed out of the way, a strange creature made out of photorealistic human body parts shows up in the shower. It then says "You should knock." as an audible voice clip and disappears into the curtain. Its filename in the graphics zip file is manners.
• The hallway preceding the DT Extraction Machine features laughing mouths on the side of the wall.

Barrier

• Omega Flowey uses some of his unused faces upon being confronted by the six human SOULs, and his dialogue is slightly altered.
  • The souls...?
  • What are they...
  • HEY, YOU GUYS AREN'T GONNA...
• Asriel has new dialogue as he is being SAVEd, which replaces his 7th turn's original battle dialogue.
  • I'm not ready for this to end.
  • It can't have been a year already.
  • It can't have been 5 years already.
  • It can't have been 10 years already.
  • It can't have been...
  • Everything, everyone I loved can't keep getting further away.
  • We can't go any further than this. Please.
  • I don't want to keep growing up...
  • Not without you.
• After the game's regular credits, a new ending graphic with the main cast appears, followed by the additional credits for the modified version of Undertale used in the stream.

Live action

The UNDERTALE 10th Anniversary Stream has two live-action segments during Day 1:

Halfway through the stream, the Fangamer Dads and the Annoying Dog leave the room. The camera pans to Spamton A. Spamton crawling through a cavern and entering the room via a slimy pink-and yellow Spamton-shaped entrance. He realizes he is unable to talk, stands up, and spins to become large. After sitting on the couch with a cartoon splat noise, HEY EVERY ! plays as he pulls a large pink-and-yellow disk from his coat. He inserts it into the TV and returns to the couch to play and move the protagonist into the Grillby's.

During Spamton's dialogue, Spamton A. Spamton changes his posture multiple times as the dialogue advances. This includes him mashing, rubbing the buttons, laying upside down, being behind the couch, appearing bored, mashing with a spoon, hopping, answering a phone, pecking with his nose, yelling in despair, pointing, or twitching. While trying to revert back, Spamton A. Spamton leaps in the air and yells before turning into a cup with S.A.S. on the back and rolling into the door. During the zoom in to the cup's face, Dialtone plays. The cup is later pushed away when the door opens.

At the end of Day 1's stream, 3D Toriel physically appears in the form of a piñata. While the other Fangamer Dads insist that Reid should not let her into the room, she enters anyways. Reid notices 3D Toriel being a piñata, takes out a bat, and as he swings, the screen glitches and depicts a hybrid of various 3D Toriel moments from Undertale trailers. Afterwards, everyone is shown unconscious and surrounded by pink and yellow candy. As the camera pans and zooms in to 3D Toriel, her eyes focus on the camera before the screen turns black.

New NPCs

Name	Image	Location	Notes
Lumberjack		Snowdin	Muses about staying in the location and only chopping trees due to resembling them. The Lumberjack also mentions that Asgore has been everywhere in the underground. In the epilogue, the Lumberjack decides to offer hats to the trees, rather than destroying them.
Noelle		Snowdin Town	Was not interacted with at all during the stream, and is not included in the official Graphics compilation. See also: Dog Shrine and Asgore's Winter Dialogue from the UNDERTALE Alarm Clock for other allusions to Noelle's Undertale counterpart.
Underwater NPC 2		Waterfall	Makes bubble noises, though the protagonist does not understand the accent.
Underwater NPC 4		Waterfall	Was not interacted with during the stream.
Underwater NPC 1		Waterfall	Makes bubble noises, though the protagonist does not understand the accent.
Underwater NPC 3		Waterfall	Has an older bubble noise dialect than Underwater NPCs 2 and 1.
Underwater NPC 5		Waterfall	Admits to wearing a "fire-proof diving suit". Appears to be a fire-based monster.
Hall Monitor		Hotland	Shares a resemblance with Fuku Fire.
Ficus Student		Hotland	Shares their appearance with the ficus licker.
Milk Student		Hotland	Shares their appearance with Milk Looker from Deltarune.
Bird Teacher		Hotland	Shares a resemblance with Berdly from Deltarune.
Hotland High Student 2		Hotland	Was not interacted with during the stream.
Hotland High Student 1		Hotland	Was not interacted with during the stream. Their face is never visible.
Hotland High Student 3		Hotland	Was not interacted with during the stream.
Temmie Student		Hotland	Temmie in a high school uniform. Was not interacted with during the stream.
Squident		Unused	Present in the graphics files but went unused. The name and outfit suggests the NPC would have been seen in Hotland High. They bear a resemblance to Skateboard Girl.
Vent Fan		Hotland	Dialogue is reminiscent of Shuttah from Deltarune. Their behavior is a joke about the frequent usage of shots of Hotland's vent area in Undertale's trailers.
Panet		New Home	Appears in New Home, painting a building orange.
Griffon Claw		New Home	-
Arbiter Crab		New Home	Is the arbiter of the "Nose-Nuzzling" tournament. Despite his appearance, he is only 18 years old.
Manners		True Lab	A creature that is revealed behind the True Lab's shower curtain before leaving. Appears to be made up of parts of one or more photos of human faces.

Incentives

Day 1

Polls

• Name choice between TOGORE and CHARA.
• Burger or Fries?
• Ketchup or Catsup?

Targets

• Get Nice Cream card ($2,500)
• Visit Napstablook ($2,500)
• Hot Dog Tower ($200/dog out of $6,000)
• Fight Muffet ($10,000)

Community goals

• Verse Sans ($25,000)
• Battle Sans ($80,000)

Day 2

Polls

• Name choice between TOGORE and CHARA.
• Essay on Mew Mew Kissy Cutie (Reviewbless or Reviewbomb?)
• Anime Is Real or Anime Is Not Real?

Targets

• Sleep at MTT Hotel ($5,000)
• Buy the Mystery Key ($5,000)
• Sleep in Creepy Bed ($2,000)
• Return to New Home ($10,000)
• Return to Old Home ($10,000)

Community goals

• Sans Attacks ($200,000)
• Ask Sans To Go All Out ($230,000)
• Toby Not Nap ($270,000)
• Surpass Spamton Sweepstakes ft. Spamton A. Spamton ($322,805.68)

Auctions

Two one-of-a-kind items were individually auctioned at tiltify.com, and treated separately from the charity event:

Item	Description	Credits	Highest Bid (Day 1)	Highest Bid (Day 2)
Giant Toriel Plush	Giant version of the regular Toriel plush. Featured on stream set with the Fangamer staff, mostly with Reid playing with it, "increasing her value". She was also subjected to Spamton A. Spamton's abrupt appearance.	Eyes5	$3,600	$11,000
10th Anniversary TV Diorama	Physical diorama of the 10th Anniversary logo, with the Annoying Dog sitting in front of a CRT featuring the seven human SOULs on screen arranged similarly to the Omega Flowey fight, a Nintendo 64, a Hot Dog on a plate, and author's signature on the back. Made from wood, wire, polymer clay, felted wool, chrome paint, fluid acrylics, and light-absorbing matte black paint. Featured occasionally in the Day 2 stream.	Camille Young	$5,000	$13,969.67

Differences from 6th Anniversary Stream

General

• An animated 10th Anniversary logo of the Annoying Dog crawling out of the CRT.
• An animated introduction segment of various Undertale characters at the Last Corridor.
• Undertale developer names, avatars, website, and contribution appears at the bottom of the screen.
• New locations unique to the stream are featured.
• Contains cameos or allusions to Deltarune.
• The Ruins set the Fangamer staff and Annoying Dog appears in has its decorations and merchandise replaced when they reach another location in the underground.

Annoying Dog

• The Annoying Dog plush's mouth moves when talking, and captions appear for Toby's text-to-speech commentary.
• The Annoying Dog's sprite appears with a dark background to occasionally cover the set camera. The dog's mouth moves along with the text-to-speech commentary, and occasionally does flips.
• The Annoying Dog sprite can turn green, often to indicate when Toby mentally blanks.
• The Annoying Dog in the 10th Anniversary logo is occasionally animated, such as dancing and shaking the maracas. The logo's background resemble the borders for console versions of Undertale.
  • Once Flowey absorbs the six human SOULs, the logo disappears entirely. The CRT reappears at the start of the Omega Flowey battle, flashing various messages until Omega Flowey breaks through, flashing question marks in various fonts and attempting to break free from the border. He is eventually stopped by 3D Toriel, fleeing for the remainder of the battle. The 10th Anniversary logo reappears as normal after the break following the battle and ending.
  • During the Lost Souls part of the Asriel battle and the first half of the True Pacifist ending credits, several talksprites submitted to the website appear behind the logo, scrolling upwards in a grid arrangement.
• The Annoying Dog gets equipped with some items from the area, such as the Faded Ribbon.

Soundtrack

Main article: UNDERTALE 10th Anniversary Stream Soundtrack

The 10th Anniversary Stream Soundtrack consists of tracks that play exclusively on the Undertale build used for the stream. After the stream ended, the tracks were publicly released on the Undertale website. On January 21, 2026, the tracks were released to Toby Fox's Bandcamp.

Intermission tracks

Tracks that played during pre-stream and intermissions, where the protagonist walks and listens to Echo Flowers that display submitted Memories. This includes fanmade music tracks from the UNDERVEIL project and arrangements from Carlos "insaneintherain" Eiene, including tracks from his Live at Grillby's album.

Title	Album	Author	Day	Time
Re-Undulate	UNDERVEIL	Kankitsu	1	00:00:00 - 00:06:18
Battle of Ordeal	UNDERVEIL	daph	1	00:06:24 - 00:11:35
Spear of Justice(MRM REMIX)	UNDERVEIL	モリモリあつし	1	00:11:42 - 00:15:35
Undersouls	UNDERVEIL	shimaL	1	00:15:44 - 00:22:06
It's a Beautiful Day Outside (MEGALOVANIA)	Live at Grillby's	Carlos "insaneintherain" Eiene	1	00:22:13 - 00:28:52
Welcome Home (Home)	Live at Grillby's	Carlos "insaneintherain" Eiene	1	00:28:53 - 00:35:40
Ice to Meet You! (Snowdin Town)	Live at Grillby's	Carlos "insaneintherain" Eiene	1	00:35:45 - 00:40:30
Hopes and Dreams "A Newer New Home"	UNDERVEIL	orangentle	1	00:40:33 - 00:44:57
Undiscardable	UNDERVEIL	Frums	1	00:45:03 - 00:49:51
Dogdance	UNDERVEIL	s-don	1	00:49:59 - 00:55:43
A Date with Demise (It's Raining Somewhere Else)	Live at Grillby's	Carlos "insaneintherain" Eiene	1	00:55:48 - 01:00:16
Fallen Down (Reprise) Butterscotch cinnamon mix	UNDERVEIL	こふ	1	02:52:33 - 02:55:42
ASGORE (Puru Remix)	UNDERVEIL	Puru	1	02:55:48 - 03:00:30
Fascinate ft. Muffet	UNDERVEIL	ryhki	1	03:00:39 - 03:04:07
Howdy! and... Good-Die!	UNDERVEIL	ゆうゆ	1	03:04:28 - 03:07:31
Only	UNDERVEIL	izna	1	05:30:40 - 05:36:51
The Incinerator (Another Medium)	Live at Grillby's	Carlos "insaneintherain" Eiene	1	05:36:56 - 05:43:07
DREAMEND	UNDERVEIL	Saiph	1	05:43:15 - 05:47:52
Ice to Meet You! (Snowdin Town)	Live at Grillby's	Carlos "insaneintherain" Eiene	1	05:47:56 - 05:53:38
Bergentrückung / ASGORE	insaneintherainmusic Year 4	Carlos "insaneintherain" Eiene	1	05:53:42 - 05:59:59
Unbelievable surrounded by Blue	UNDERVEIL	Tanchiky	2	00:00:00 - 00:01:15, 02:32:45 - 02:36:14
DREAMEND	UNDERVEIL	Saiph	2	00:01:15 - 00:06:00, 02:36:14 - 02:41:00
The Incinerator (Another Medium)	Live at Grillby's	Carlos "insaneintherain" Eiene	2	00:06:00 - 00:12:15, 02:41:00 - 02:47:13
A Mother's Love (Heartache)	Live at Grillby's	Carlos "insaneintherain" Eiene	2	00:12:15 - 00:16:56, 02:47:13 - 02:48:02
The Star of the Underground	UNDERVEIL	Kiryu	2	00:16:56 - 00:21:57
Ruins	insaneintherainmusic Year 5	Carlos "insaneintherain" Eiene	2	00:21:57 - 00:28:14
Welcome Home (Home)	Live at Grillby's	Carlos "insaneintherain" Eiene	2	00:28:14 - 00:35:04
NEVERAGAIN	UNDERVEIL	Silentroom	2	00:35:04 - 00:40:08
Only	UNDERVEIL	izna	2	00:40:08 - 00:46:24
Undertale (feat. SwigglesRP)	insaneintherainmusic Year 5	Carlos "insaneintherain" Eiene, Ro "SwigglesRP" Panuganti	2	00:46:24 - 00:51:22
Fallen Down (Reprise) Butterscotch cinnamon mix	UNDERVEIL	こふ	2	00:51:22 - 00:54:44
Undiscardable	UNDERVEIL	Frums	2	00:54:44 - 00:57:50

Gallery

• 
  The Annoying Dog "poisoned".
• 
  Map of new area in the Ruins, Home.
• 
  Map of new area in Snowdin.
• 
  Papyrus in his "COOK DUDE" attire.
• 
  Punch Card.
• 
  Underwater Town, a new area in Waterfall.
• 
  Hotland High, a new area in Hotland.
• 
  Mettaton dressed up as an "exchange student" at Hotland High.
• 
  First of the new faces of Omega Flowey.
• 
  Second new face of Omega Flowey.
• 
  Third new face of Omega Flowey.
• 
  New area in New Home.
• 
  Glyde's overworld sprite, as seen in Snowdin.
• 
  Vitamoid.
• 
  Wintercoat.
• 
  Gerson's overworld sprite, as seen in Home.
• 
  The ending scene before the stream credits.
• 
  The message at the end of the stream.

Trivia

• In the edited wrong number song, the caller mentions that their favorite "M**vel Superhero" is "D**key Kong!", referencing a variable known as donkeykongismyfavoritemarvelsuperhero.
• When inspecting Papyrus in his "COOK DUDE" outfit, there was dialogue written related to checking his "fried chicken legs". This dialogue was jokingly referred to as "lost media" by Toby as it was exclusive to the stream's version of the game yet was not read by the players.
• The sound played after entering and exiting the Ruins (and at the various endings) is a noise made by Toby's mouth.

The fox that Toby repeatedly showed off, drawn by Cap.

• The CORE was the only area that did not have new content, thus Cap's spritework of "foxradiation" was repeatedly shown during that section of the stream, as well unused concepts as text files. Cap comments that this fox was drawn on "a funny whim" back in 2013.
• During the date with Alphys, Toby Fox remarks that he just noticed Sans holding a plate of corn offscreen. This is a reference to an infamous Twitter post made by @hourlydolores with a similar statement regarding the 2021 Disney film Encanto, widely known for pointing out an exceedingly obvious and insignificant detail.
• In the True Lab, Toby mentions a famous story about a dog repeatedly searching for a pie in a bush. This is a reference to a viral tweet about someone's pet dog.

See also

• Undertale's Anniversary section
• UNDERTALE 10th Anniversary events
• Deltarune's Anniversary section on the Deltarune Wiki
• Spamton Sweepstakes article on the Deltarune Wiki

External links

• UNDERTALE - Memories
• UNDERTALE - Memories, archive.org version from July 26, 2025. Information sent is not saved on the official Undertale website. It does not use 8bitOperatorPlus-Bold font on download, and avatar art cannot be properly downloaded on mobile.
• Battles against Sans, Mr. Sunshine and Abberant