Canon Underswap Wiki

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— Sans's catchprase

Sans is the older brother of Papyrus.[2] He is training to become a royal guard with Alphys.[5]



Sans is a chubby skeleton who wears a light grey shirt with a white shirt underneath, dark blue pants, and blue boots. He wears a blue cape around his neck, which ends near the end of his shirt.[2]

His eyes, which he can turn into hearts or other different shapes to express his emotions[6], are light blue with two dark circles in them. Unlike Undertale's Sans, he has eyebrows and can open his mouth.[2]


Sans is excitable, loving, and enjoys making tacos for his friends.[1] He calls himself "The Sansational Sans" and "The Supreme Sans".[7]

Sans likes to make tacos and burritos instead of spaghetti (Italian food being swapped with Mexican)[8] and likes to say "MWEH HEH HEH or HEH HEH HEH", he also likes riddles instead of puzzles.[8]

He enjoys making puns and pranks.

Sans enjoys collecting sci-fi figurines and spaceships (as well as other snippets).[9]


During his fight, Sans inflicts KR on Chara and turns their SOUL blue.[2]

Main Story[]

Neutral Route[]

Sans sets up various traps to stop Chara.[6]

After his fight, he takes Chara on a date[10], where he wears a shirt with "rad dude" written on it.[11]

Genocide Route[]

When Sans is fought, he tells Chara to run into his arms, before getting killed.[12] However, if you spare him in the Genocide Run, this will end the Route. (just like if you will spare papyrus on genocide in undertale)



Papyrus is Sans's younger brother. Sans sometimes shares his tacos with him.[2]


Alphys trains Sans.[5] She also sometimes helps out Sans with his cooking.[1]


  • MWA![6]
  • COME INTO MY ARM- oh..[13]
  • i guess this is goodbye.[13]


  • Sans speaks using uppercase letters, using the Comic Sans font.[14]
  • Sans is the first Underswap character that popcornpr1nce created.[2]
  • Song That Might Play When You Fight Sans was popcornpr1nce's original choice of theme for Sans, because it’s cute and upbeat. But he finds remixes of MEGALOVANIA pretty sweet too.
  • Sans says "WOWZERS!" when amazed, similar to how Undertale Papyrus says "WOWIE!".[15]



  1. 1.0 1.1 1.2 1.3 about & F.A.Q Official Underswap Tumblr
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 OK SO, I thought what if theres an AU in which the... popcornpr1nce's Tumblr
  3. 3.0 3.1 Cite error: Invalid <ref> tag; no text was provided for refs named song
  4. 4.0 4.1 4.2 Out of curiousity are Sans and Papyrus stats still the same in this AU or are they switched as well? Since it would make a lot of sense for Sans to be denied into the Royal Guard if he still had only 1 HP and 1 ATK. After all if anyone were to lay a hit on him he’d turn to dust instantly. Official Underswap Tumblr
  5. 5.0 5.1 Would sans still be friends with toriel and that's why he really wants to be part of the royal guard? popcornprince's Tumblr
  6. 6.0 6.1 6.2 more of the underswap au that no one asked for but... popcornpr1nce's Tumblr
  7. does sans refer to himself as 'sans the great' like how papyrus does it in canon or is it something else like the 'sensational sans' or something like that? Official Underswap Tumblr
  8. 8.0 8.1 hello yes i would like to write some underswap fanfic, can you give us anymore headcanons? like who else has swapped and whatnot? and does sans still like puns or is that Papyrus' thing? does pap still make spaghetti? popcornpr1nce's Tumblr
  9. So you know how papyrus collects action figures in undertale? What if underswap!Sans collects you spaceships
  10. Wait. Since it's swapped... wouldn't that mean that you'd go on a date with Sans instead of Papyrus? Official Underswap Tumblr
  11. the most important question: would sans wear a "cool dude" shirt on the date with him or no (and is there anything else that is different about this. im asking for a friend) Official Underswap Tumblr
  12. “take one more step, and you’re gonna have a bad time kiddo” popcornprince's Tumblr
  13. 13.0 13.1 “take one more step, and you’re gonna have a bad time kiddo” popcornprince's Tumblr
  14. So will Underswap!Sans still talk in Comic Sans but in all caps? And likewise for Underswap!Papyrus talking in lowercase? popcornprince's Tumblr
  15. Think Sans would say something like "WOWZERS!" instead of "WOWIE!"? Official Underswap Tumblr