Underfell Stories

You're a human that has fallen into Mt. Ebott on the year where all humans dress as monsters...Halloween. So how will the monsters know if you're a human or not?

"How rude, not even gonna ask for a name??" He teased. "Why are you here?" You glowered, raising the whisk. The skeleton scoffed: "Well, glad yo...

You were afraid. For the first time in your life, you were truly afraid. You weren't afraid of the never-ending darkness that had now consumed you. You weren't afraid of...

This will be my first book so please no hate. I am trying to make the book for both genders so if I wrote something for a specific gender please tell me. If you dont lik...

(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...

[Disclaimer that this book is very old nd poorly written, please keep that in mind!] You were shy. You were small. You were picked on. You were told you weren't tall eno...

What if someone died and was reborn in an undertale au as a siren? And not just any kind of siren, but a sans, a skeleton siren. They can change back between full skelet...

Sans and Papyrus were your best friends until randomly they just cut off all contact with you. This went for everyone else in your life so it didn't really hurt that muc...

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...

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'...

Hi guys! First of all I should mention that the story pic isn't mine and of course Fellswap belongs to its original creator. A young hiker, Y/N gets lost and accidental...

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. ...

It has been 10 years since the monster broke free from the barrier, and since then monsters and humans live together in peace. But for some reason, monsters have somehow...

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...

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

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...

Moved from AO3 because of reasons! "You are the only maid (or worker in general) that serves for the Skeletal Household. It's a skele-ton of work, but you manage by...

**PLEASE NOTE** -Cover art does not belong to me, I will only take credit for the stories, I do not take credit for characters. -I will not do any lemons -This is my fi...

One clumsy moment and a broken leg are all it takes to leave you at the mercy of the very edgy and very hostile monsters of the underground. Thanks to your knowledge as...

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...