This is the first AU that I made, so it's bad. Just keep reading.
Undergoop Sans wears no clothes, but will wear a trash bag to parties sometimes. His body is not the blackest black but black anyways (did that sound racist to anyone else? No? Okey.) and he wears an orange collar with a skull and bones on it. He wears a belt where his pelvis/lower torso should be so that he doesn't melt everywhere. He has white circle eyes like the normal Sans and, miraculously, his head is still in head formation.
A terrible incident happened when Frisk reset but something went wrong. Everybody melted (Gaster was over in his corner with a dunce hat on and he was laughing his head off because now they were all melty and goopy) and became a bit more crippling depressed. Except Sans, he found Gaster and they're friends now. Frisk returned as a human with black angel wings and a black halo that was broken in half. Everyone was furious with Frisk. Except Sans, he was too busy with Gaster. Later he entered the Multiverse and became a specimen.
I made a Sans that I thought was going to be Reaper Sans but thank god Reaper Sans already existed then I got rid of him for sometime and now he's back.
Goop- This is when he tries to "goop" Frisk by falling over Frisk by taking their belt off. He rarely uses this attack because he has like three minutes to grab the belt before he melts into the ground.
Magic eyeball onion ring of doom- His glowing eye is white but it fuels his attacks with magic.
Gaster Blahsters- Seriously, these things are so gross that the word "blah" is in the name. They don't do much damage, either.
Bones- You have three guesses.
If you manage to escape Sans' goop move (which I doubt will happen) you have three minutes to stab him. Or you can just move his belt out of his reach and listen to him call out to his friends for help while crying for mercy and pleading for you to give him the belt back and laugh before he sinks into the ground. He also has Bananaphobia because he once turned the color of a banana after eating one, so paralyze him when you have a banana handy during a fight.
- He absolutely hates work.
- He isn't allowed to play video games or watch TV (due to Papyrus saying "SANS! IF YOU WATCH TV OR PLAY VIDEO GAMES, YOUR HEAD WILL BECOME MUSHY AND DEFORMED TOO!")
- He likes being around other people.
- He hates being alone.
- He knows that Frisk really isn't that evil, the other reason that he actively doens't try to kill them. Frisk manipulated something in the files so that there could be two Undergoop Sanses- this one, and a version with the Trickster Virus.
I'm sorry that this was so sarcastic I just really don't like this AU even though I made it whatever I don't hate you all really I don't goodbye