Thundersnail

For the track of the same name, see Thundersnail (soundtrack).

Thundersnail (JP: サンダースネイル) is a minigame that the protagonist can play by spending 10G at Napstablook's snail farm in Waterfall. If the protagonist does not have 10G, Napstablook still allows them to play, taking whatever money they have.

The minigame is unavailable during the Genocide Route, as both Napstablook and the snails are absent. It is also unavailable during the True Pacifist Route epilogue, as Napstablook remains near their house and will not appear near the racetrack.

Gameplay

Thundersnail consists of three differently-colored snails on a race track, with the yellow snail being the one the protagonist must cheer for. A blue snail is situated at the bottom, a red snail is positioned in the middle, and the yellow snail takes the top lane. The game ends in a victory if the yellow snail wins, and a loss if one of the other two snails wins.

To win the race, the protagonist can encourage the yellow snail with the [CONFIRM] button every time the exclamation mark above the snail is not visible. Each encouragement causes the snail to stop in her tracks, then crawl faster. Too much encouragement, however, causes the snail to flip over and combust into flames.

Rewards

Napstablook offers a reward if one of two feats is achieved:

• If the yellow snail wins the race, Napstablook awards 9G, 1 less than the entry price.
• If the yellow snail loses by a thin margin, Napstablook awards 30G to not disappoint the snail.

Strategy

Each snail races at a set speed, which changes depending on how many times the protagonist encourages the yellow snail. By default, the yellow snail cannot win unless encouraged enough times, but if encouraged too rapidly, her pace becomes slower than her default speed, eventually slowing to a halt.

The red snail, by default, wins the race after 39 seconds pass, defeating the blue snail by 11.5 pixels. If the yellow snail flips upside down, this spurs the red and blue snails to race faster toward the finish line. Depending on the timing of the excessive encouragement, the blue snail can overtake the red snail and win the race.

To win 9G consistently, encourage the snail 10 times at the start of the race, whenever the exclamation mark is not present.

To win 30G consistently, encourage the snail 7 times at the start of the race, whenever the exclamation mark is not present. The snail will then have just enough speed to always win by a thin margin. This is one of the ways to farm money in Undertale.

Gallery

• 
  Artwork from Undertale's 5th anniversary

Trivia

• The minigame is likely a reference to the SpongeBob SquarePants episode, "The Great Snail Race". In the episode, SpongeBob enters his snail Gary into a race, but because of being overworked before the contest and being pushed too far during the event by SpongeBob's abusive "encouragement", Gary veers far off course and bursts into flames.