Gaster

Gaster is a character in Underfell.

Design
Gaster is a thin white monster with deformed black eyes, sweat, a mouth red on the inside and two white hands with holes in them. He wears a black cloth that fully covers his body and is wider at the end. He holds a silver mug and seems to be surprised when it disappears.

Personality & History
He had a lot of responsibility pilled onto him, he's misunderstood and comes off as wacky or a mad scientist but he's really just stressed. He was the monsters last hope to get out of the underground but he had very little hope himself in getting out in the first place and when he met a dead end with his research he dissapeared, it's not clear why or what exactly happened to him.

Sans and Alphys worked with him in the lab. 

Trivia

 * Underfell's creator was unable to make Gaster edgy.
 * https://underfell.tumblr.com/post/185264510156/what-is-gaster-like-in-this-au-if-you-dont-mind