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Waterfall is the area where you meet Undyne for the first time. It is home to many different monsters, including Aaron, Woshua, Shyren, Temmie, Moldybygg, Mad Dummy and Undyne. The dump is also in this section of the underground. There are also two different shops you can visit, each with distinct items. Napstablook and Gerson both live here. The player can also take part in the snail race here.
The two shops are Gerson's shop, and Tem Shop located in Temmie village. The Tem shop is also the only place in the underground where items can be sold. Most items the player sells will be sold at a loss with the exception of the cloudy glasses (which can be sold for a 20G profit). This is the only real use for the Dog residue obtained by doing the piano puzzle.
The Items obtainable in Waterfall are below:
|Temmie Flakes||3G||Tem Shop||Any Route|
|Temmie Flakes (Sale)||1G||Tem Shop||Any Route|
|Temmie Flakes (Expensiv)||20G||Tem Shop||Any Route|
|Temmie Flakes (Premiem)||1000G||Tem Shop||Genocide Only|
|Tem Go to Colleg||1000G||Tem Shop||Neutral/Pacifist|
|Tem Armor||700G (Price drops with each death)||Tem Shop||Neutral/Pacifist|
|Crab Apple||25G||Gerson's Shop||Any Route|
|Sea Tea||18G||Gerson's Shop||Any Route|
|Cloudy Glasses||30G||Gerson's Shop||Any Route|
|Torn Notebook||55G||Gerson's Shop||Any Route|
|Astronaut Food||Free||In Dump||Any Route|
|Ballet Slippers||Free||Scattered||Any Route|
|Dog residue||Free||Piano puzzle||Any Route|
Undyne (Pacifist/Neutral) or Undyne the Undying (Genocide/Neutral)
Aaron (Any route)
Shyren (Any Route)
Woshua (Any Route)
Moldbygg (Any Route)
Mad Dummy (Neutral/Pacifist) or Glad Dummy (Genocide only)
Monster Kid (Genocide only)
MAD DUMMY GETS MAD
Monster Kid Takes action
MTT's Old home (Presumably)
Blookies Music scares the bajeebs out of people
AU's Waterfall is in
You can activate a hidden room with an artifact inside.
The piano puzzle was created by Undyne.
MAD DUMMY IS PEEVED
The waterfalls go farther down than the protagonist can see