Underswap Stories

Mainly what the title says. Lots of Sans, ton of SANS, Undertale sans, undefell sans, ALL THE SANS. BUT WITH A CHUBBY READER. WHHHAAAAT I KNOOOOW. READ FOR THE FLUFF...

(I DO NOT WRITE ABOUT UNDERTALE ANYMORE SO PLEASE DON'T REQUEST ON MY CHAPTERS) (AND FOR THE LOVE OF GOD STOP COMMENTING ABOUT MY GRAMMAR, I AM SWEDISH AND I HAD A HARD...

(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...

Note to self: Never make jokes about getting reincarnated into a video game character because it'll actually happen. Welp too late to go back now, considering I'm alread...

Sanses included will be...Classic, Swap, Fell, Swapfell, Ink, Error, Dream, Nightmare, Dust, Killer, Lust, Horror, and Fresh. Please be aware that the pronouns used for...

After Blue's "kidnapping" Blue is returned with an Error doll. Everyone thinks it's creepy, but what happens if it's taken away or destroyed? Then there's a wh...

You were a kind human who has a brother named Frisk. You and Frisk always get along until both of you climbed up a mountain. very curious if the legend was true or not...

Humanity is divided over one thing---the Monsters' reappearance. Some believe that they should stay aboveground, and others think that they should be sent back to where...

Blue is sick of being treated like a child by his friends and family. He shoves down his negativity in order to stay 'happy' like they want though. Nightmare has had eno...

[Previously known as "But He Never Showed It"] Sans has been hiding something lately.. Will Papyrus figure out what's really been going on before it's too late...

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

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...

Who thought that one day someone would break into your house and slice your neck in your sleep? Well, that was what happened, right before you were integrated into a shi...

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...

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...

In order to be seen as not soft Nightmare buries his feelings down deeper than his soul. What will happen when those feelings start to rise to the surface. Will there be...

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...

When your sibling Chara goes missing you fear the worst, but life takes a surprising turn for the better when they release the monsters trapped underground. Living this...

If you can't tell what this is from the title idk what to tell you... I will do requests and they can be as detailed or as vague as you want. I will do OCs if you want. ...

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...