Mass Genocide Sans

Mass Genocide Sans is a Sans that, as his name suggests, did a Genocide Route in the Underground, and killed the same people in other timelines, or a Mass Genocide Route (what occurs after a Soulless Pacifist Ending in Undertale). He became insane and glitch hopped into other timelines (including Pacifist and Neutral route timelines) to kill more monsters and humans.

Undertale Remix - MEGALOVANIA - Nitroglitch06:34

Undertale Remix - MEGALOVANIA - Nitroglitch


IMG 00100

Mass Genocide Sans usually wears a white hoodie with dark gray all over it. The middle of his hoodie has a red heart on it, and he always keeps his hoodie unzipped, to represent the heart being broken. He wears silver shorts and red bunny slippers. He has two white eyes like the normal Sans, and one blue glowing eye. He sleeps naked and has swimwear shorts with black and white checkers on them.


Once Frisk did a genocide run, and they soon met up with Sans. "You killed my brother, now I'll kill you." He was going to try and use the CORE to get to another timeline. Before he could do that, though, he had to make sure that he killed Frisk first so that he could do it without getting killed. The fight progressed, and soon Sans was killed. Sans later woke up in his bed, and tears were running down his face. He got up. Papyrus screamed in his raspy voice,

"COME SANS! YOU CANNOT SLEEP FOREVER! WE MUST GO PATROL FOR HUMANS!!!! NYEH HEH!" Sans got up and dressed. He walked outside, only to see Frisk standing at the gate. Frisk turned around and smiled. That's when Sans realized that Frisk was doing a pacifist run, and he was furious. How dare they do pacifist to cover up a genocide! Frisk put up their hand, but Sans slapped it and stomped up ahead. He returned a few seconds later with Papyrus. Frisk ran ahead.


Sans was too angry to speak. Earlier, he was ratted out by Papyrus, kept tripping on ice, the lady at the door refused to answer, couldn't go to Grillby's because it was closed, and now he's tangled up in a huge vine by some weird flower thing! How much worse could this get?

He woke up. Frisk reset...again! That was it. As soon as Frisk made it to the Judgement Hall, he confronted them and asked about the resets and why. He noticed that Frisk was holding a dust-stained knife. "You're killing everyone. You dirty brother killer, no wonder I found my brother dead! It was all you. You killed everyone that I loved, now it's time I do the same to you." And with that, he ran down to the castle. Asgore stood there, oblivious to Sans. Sans struck him through the heart with a bone, and Asgore trembled a bit before he faded to dust. Flowey popped up. "S-Smiley Trashbag?"

Then, Sans ran back to Hotland and straight through the CORE. He passed broken robot parts, blood stained through the halls, and countless piles of dust. None of them were his. Yet. As soon as he saw Alphys, he ran to her and beheaded her with another bone, this one blue. Alphys' face was a mix of rage, betrayal and confusion, before she shut her eyes and turned into a worthless pile of dust. Sans didn't know why, but he started to get a cold feeling of discontented satisfaction. He took the boat to Waterfall all by himself. He killed the Riverperson when he saw them. Flowey held his breath as he held on to the bottom of the boat. Then Sans sailed back to Waterfall to wipe out everyone. He didn't want to fight Undyne because he knew that he couldn't get past her. Luckily, that was already taken care of. Finally, he ran back to Snowdin and finished everyone off. The Ruins were empty. Seems like Frisk decided to abort a Genocide Run. Flowey followed behind, lurking in the shadows. He ran back to the Judgement all and into the castle to see Chara. But nobody came. He wondered why. Did he miss someone? Flowey spoke up. "Hey, Sans...what are you doing?"

Sans whirled around. There was Flowey, the last one to kill. He prepared a Gaster Blaster, but Flowey ran away before Sans could use it. Sans started to laugh. What a day! He fell asleep as soon as he got back to Snowdin. When he woke up, he was in another timeline. This one was Genocide. Frisk was at the Judgement Hall, preparing for the real battle to begin. He teleported there, killed the first Sans (while Frisk obnoxiously stared), and got into position. He fired his blasters, he used bones, he threw them up and down, and when he was done, music faded in. "Look familiar, kid?" He killed Frisk while he still could. He ran to kill Asgore, and when he came back, something in the distance caught his eye. A flower? Oh, it's Flowey! And a reset button? ERASE button. Flowey looked up and froze like a deer in headlights. Sans started to run to Flowey. As hard as he could, Flowey slammed a vine on the ERASE button, and the world began to crumble. Flowey used a hack to escape into the files of Undertale, while Sans was just stuck. Sans screamed, but to no avail. He curled up into a little ball, as the world made it's final act and disintegrated into nothingness.

When Sans woke up, he was surrounded by maddening blankness. He stood up, but soon fell back down. His legs felt like spaghetti. And he was dizzy and nauseous. Eventually, he regained his balance and started to walk around. He wanted to explore. He ran, but everything was the same. Where was he? Sans started to laugh, and he started to lose his sanity. He said some things out loud, and his sanity withered away, until all that was left was a skeleton with no mind. He curled up on the ground, and that's where he is now.


Error kicked Sans, and left. He later returned with his friends, Underswap Sans, and Bete Noire. A soccer game resumed.


Normal Sans Powers- Default Sans powers

Glitch Hop- He uses this to escape into other timelines

Everlasting Memory- He remembers everything

Spindash- Same as Sonic, but less effective and he can't knock people out with it


He has a severe allergy to strawberries, and he won't go near one. He is fearless due to his insanity.


Annoying Dog
This information is based on alternate scenes or materials, and is not considered canon within the overall plot of the AU series.
Mass Genocide Flowey- He hates him, despite Flowey only doing what he did out of self defense.

Error Sans- Error Sans kicked him once and then proceeded to leave. Sometimes, Error Sans plays soccer and uses him as the ball.

Infected- Though only hearing about him from eavesdropping in on the other Sans' conversations when taking a break during soccer, he pledged to kill him if he finds him.

Tricksterberry - He has a crush on him. Which is funny, considering that he disliked usual Blueberry. He calls him "Sugarberry" or "Colorberry" sometimes.


  • He likes Glitch Hop music, forcing him to call his attack/teleportation method "Glitch Hop".
  • He did not go insane from killing, he went insane from the Anti-Void's eternal whiteness. Just in case that wasn't clear.
  • He doesn't want to be a soccer ball, he wants to be a basketball.
  • He has a crush on Dark! Sans, made by RlopKid.
  • He likes Sonic.
  • He despises any hot or fried foods.
  • The reason that Frisk didn't respawn after Sans killed them is because Sans had gained too much determination for Frisk to revive, but not enough to take control of the save files. AU rules.

Ad blocker interference detected!

Wikia is a free-to-use site that makes money from advertising. We have a modified experience for viewers using ad blockers

Wikia is not accessible if you’ve made further modifications. Remove the custom ad blocker rule(s) and the page will load as expected.