Out of courtesy, we ask that you please respect popcornpr1nce's wishes and do not bother him with anything Underswap-related. He doesn't want anything to do with it for his own personal reasons, mostly because of how the fans have treated it.

If there is anything you need to know about "canon" Underswap, please use the link in the infobox to the right to visit the archived blog for it.

Underswap is an Alternate Universe among the many different swap based worlds, with this being the very first of its kind. It switches the characters in the game who have pairs with each other, along with switching their personalities.

About the AU

Stated in original blog, the AU was always meant to switch not only the roles, but the personalities of almost every main character, along with occasionally switching interests for some characters, such as changing Sans' iconic food to Tacos instead of Spaghetti, along with changing the laugh to "Mweh heh heh", but popcornpr1nce's personal blog still states that Sans is a skeleton who would make puns.

Though, in many interpretations of Underswap, people didn't apply the part about Sans still liking puns and many treat Sans as if he hated them. Many end up going for a full personality swap in that regard.

Since then, popcornpr1nce has abandoned the idea and concept of Underswap due to not liking how the fans have treated it, due to turning Sans' behavior in many common interpretations into the likes of a child, and giving him the name "Blueberry", and Papyrus the name "Carrot".

Notable Changes

Character Changes

Canon swaps[1]
Chara & Frisk.
Temmie & Flowey.
Asgore & Toriel.
Mad Dummy & Ruins Dummy.
Mettaton & Napstablook.
Papyrus & Sans.
Burgerpants & Nice Cream Guy.
Muffet & Grillby.
Alphys & Undyne.
Asriel & Monster Kid.
Bratty and Catty & Royal Guards 01 and 02.
W. D. Gaster & River Person.


  1. about & F.A.Q, Tumblr.