Sans is one of the major antagonists of Underfell AU. He is the brother of Papyrus and takes on an appearance similar to the Sans of Undertale. Sans is still lazy and dislikes puns but instead he likes knock knock jokes. And can be tired, loves relish and mustard.


Underfell Sans looks very similar to his Undertale counterpart. He is a skeleton with sharp teeth, with one being gold. His left eye is seen to be glowing red almost constantly, and he has bags under his eye sockets. He wears a black winter jacket with a fur hood and a gray cotton hoodie, and a red sweater with black pants that have yellow stripes going down. He wears black shoes with red socks or even red slippers. Sans wears a black jacket, with the "fluff" at the collar being notably more ruffled than the original Sans'. His shirt is a red color in contrast to the normal white shirt. His shorts have a yellow strip instead of a white one and he wears black/red/white shoes or red slippers, as opposed to his counterpart's light blue slippers. His body structure appears the same as his counterpart (besides his teeth).


He is not into puns that much but he likes knock knock jokes. He is often tired because of his jacket he still wears it because it makes him look "cool". He likes mustard and relish. And he also strives to be cool just like his brother.

Powers and Abilities

Sans is a little more powerful than his Undertale counterpart. He can manipulate sharp bones and telekinetically move a living soul at ease. He can also manipulate Gaster Blasters, and is sometimes shown to be able to manipulate gravity and can recall each timeline that Frisk resets and saves.



Sans and Papyrus care for each other and Sans calls Papyrus "boss" in any stupid vartion


Sans strongly dislikes Flowey because of his frailty. sans knows of Flowey's existence and wishes to kill him.

Fell Sans

Grillby Grillby can get pissed off of Sans because Sans pays Grillby in socks and it pisses him off but Grillby still puts it on his tab.






Sans is shown to have met Alphys before, possibly from when Gaster was the royal scientist. He seems to be good co-workers with Alphys.


  • It seems that Sans plays Basketball in the Ballin' Comic and has a basketball suit.


Canon Underfell Sans - Created by Vic the Underfella

Underfell Ballin' Suits - Created by Vic the Underfella

Canon Underfell Gaster Blasters - Created by Vic the Underfella

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