Underswap Stories

You were always put in second place due to your sister being favored over you. No matter what you did it always seemed that you both were competing against each other. Y...

Kinda like discord but with the Undertale Aus this will be very stupid

Yeah sorry gained an idea on if someone became swap Gaster Also they may be apathetic or just confused on their feelings and MAYBE Autistic, I may be a bit wrong on ap...

What if someone died and became the tree of feelings from dreamtale? Well things won't stay the same, that's for sure. (Different everything etc, different personalities...

there are four timelines together(they live in peace on the surface.) underswap, underfell,swapfell and undertale timelines. by this story I about sans and grillby. ok s...

this Is a story where you Can choose what happen in the end so be aware of that ^^

I found this pictures on deviantart,pinterest,google and Frans Amino

A picture perfect family hides the fact that your life is filled with manipulation and abuse. When you move away after high school, you encounter more than one skeleton...

This story takes place after the player vanishes from their fight with the bad time trio aka Sans, Shift, Stretch. The three got stuck there for a very long time until a...

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What if someone from our world became error and didn't destroy au's and left that for nightmare and his gang and claims au's? ( different things including personalities

What if someone is reborn as Error? What if they aren't so bad? What if they're suffering in silence and keeping their job a secret for fear of hate? How will Ink react...

Y/n L/n. A special human with a special SOUL. Yes, her Soul Trait is something new. But other than her SOUL trait she has another secret. One day, while she was at the...

Somehow...I've become a sans...and not just any sans.. I'm classic!? What the flip is going on!? Wait why are different sans and papyrus's showing up at my home? I didn'...

So harem book of Charas and Frisks x male reader but real description is below this. The only one of his person in all universes is part of Undertale with an OP powers b...

(As far as I know, no one has made a story about naturetale like this so..and the only reason why I writing one like this is because of fatal error part 5? Or part 4, go...

What if..someone from our world was reborn as fellswap sans? But an accident when he was young leads to becoming blind for a long time and papyrus feels guilty about not...

What if someone became papyrus from underswap? What if they gave their brother more freedom? What if they were the one that error kidnapped instead of sans? (Things wil...

Bitty! US pap x reader x Bitty! US sans Our two little bitties have been through a lot, so what happens when they meet a human that's hurting just as much as they are...

this is a love story between swap sans and the reader, the reader falls runs threw MT.Ebott trying to escape her twisted guardians when she is shot into a massive hole...