Underswap Stories

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...

Sans AU's X Reader X Papyrus AU's (Girls only!) (FASTER UPDATES ARE ON QUOTEV!) (#ShoeTheTape) You were a quiet, anti-social girl with a big house you've got from your...

what if someone reincarnated as underswap sans and they kidnap error instead of being kidnapped by error? let's find out hehehe... This is no Blue or Blueberry . Cover...

Who would have thought that being bored in quarantine would result in being sucked in into the worse dating sim ever? Well, (Y/n) never believed that would happen, until...

(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...

Fun Fact - Dream/Blue is my comfort ship, and they deserve a book all to themselves. Art is by Mega-Loser-0 on Tumblr.

I wanted to try it out do why not?

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...

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...

Nightmare found a young child a long time ago. When they fell into a coma it sent him over the edge. several hundred years later the child wakes up in a castle of darkne...

Nightmare x Blueberry! don't like the ship? what are you doing here then?! anyway Nightmare gets a hold of the liquid version of a negativity apple and forces Blueberr...

**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...

(Discounted for a rewrite) A shy girl dies in her reality saving a kid from a speeding car founds herself trap in the anti void as a being called Error Sans the god of d...

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...

This story is about a version of Error who destroys not because of fate and not because he is crazy, oh no... here, Error destroyed because he wanted to die. all he wan...

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...

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...

[𝐀𝐔𝐒 𝐗 𝐑𝐄𝐀𝐃𝐄𝐑] "𝙸𝚏 𝚢𝚘𝚞 𝚝𝚊𝚕𝚔 𝚝𝚘 𝚖𝚎, 𝙸 𝚌𝚊𝚗 𝚑𝚎𝚕𝚙 𝚢𝚘𝚞" --------------------------------------------♡♡♡♡♡♡ ♡One moment she was sle...

Basically someone(reader) dies and gets reborn as Impact if you don't know who that is they are the son of Papyrus and Mettaton M4dh4ttey is the creator of Impact along...

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...