Part 0: https://undertale.wiki/d/t/underflub-undertale-bloopers-chapter-0-intro/340
Part 4: https://undertale.wiki/d/t/underflub-undertale-blooper-au-part-4-failed-spikes/1406
[Main Stage]
Toriel:Okay, Frisk, I have one final test. I’d like you to walk to the end of the room by yourself.
Frisk:Alright, that’s easy! *starts moving forwards*
Toriel:Err, no, not yet. I have to leave the room, first. THEN you go to the end of the room. By yourself. Without me there. …Forgive me for this. *leaves*
Frisk:…
*Just wait for Toriel to get out of sight. Then progress forwards. This is easy.
(*Frisk moves forwards and reaches close to the end of the room, but spots Toriel*)
Frisk:Oh, hey Toriel! Oh, I thought I was…
Toriel:Oh? Nope, I was behind the pillar this whole time! It was a test of independence. Though, you weren’t supposed to see me that early… Err, you still pass though! Now, I have some errands I need to attend to, so you’ll be alone for a while. Please stay here, it’s dangerous to explore by yourself I will return shortly.
Toriel:Oh! I have an idea! I will give you a CELL PHONE!
*You got the CELL PH- huh?
(It’s the upgraded cell phone Alphys gives you)
Toriel:Erm, wait! That was… the wrong one. I’ll need it back, that belongs to a friend of mine.
Frisk:Why haven’t you given it back to them yet?
Toriel:Erm, they wanted me to keep it safe while they were, um.. conducting important business. They can’t have their phone on them while they’re working, so they gave their phone to me for safekeeping until their business is over and they can retrieve it back from me.
Frisk gives the phone back, and receives the correct phone
Frisk:..Wait, why is this one ancient? The other one was better!
Toriel:I’m afraid this is the only extra one I have. But you can still call me! And I can call you! So we can stay in touch while you wait!
[Backstage]
Flowey:Wow, Toriel, you keep screwing things up!
Bravery:Flowey, you’ve kept screwing things up too, you don’t get to make fun of Toriel.
Integrity:That was a good save, Toriel. Saying the other phone belonged to someone else you knew, that is.
Snowdrake:Wait, why are there two? I thought it was the same phone and Alphys upgrades it?
Patience:Alphys can’t actually fully upgrade phones in 10 seconds flat. We simply make it look like she can by having two props, the “original” phone, and the “upgraded” one. Alphys keeps the updated one in sync with the original as Frisk goes through their journey. When Frisk hands the phone over to get upgraded, Alphys will simply play the sound effect, then hand Frisk the upgraded phone, while the original gets moved backstage to complete the illusion.
Integrity:…Hopefully Frisk won’t remember already seeing that phone when we get to that scene…