Underswap Stories

1.2K Stories

My Itty Bitties by ItsSwapPapyrus
My Itty Bittiesby Teutonic
A box has been left at your doorstep. thinking that someone must've given you the wrong mail, you take it inside and wait for someone to come by and claim it. When a wee...
Bitty Bones Scenarios  by LunarIsBoredLol
Bitty Bones Scenarios by Nov
Undertale bitty bones! (Under editing)
Shattered & Corrupted (An Undertale Sanscest Story) by DahliaMelon
Shattered & Corrupted (An Undertal...by Dahlia ♡
CROSSMARE ♡ Nightmare meets his estranged brother, Dream, under a desolate tree which formerly held the very apples that split them apart. Little did he know that Dream...
Lost Boy by balthazar5150
Lost Boyby BabyYoda
when blue let's undyne do a test on to see how bright and happy his soul really is and too see how he sees everything the way he does it starts off fine but during the...
The Trio of Remnant Chapter 1: Hatred (Male Sans Reader X Blake Belladonna) by Icetome
The Trio of Remnant Chapter 1: Hat...by Icetome
This is my first story and it will be about RWBY and the bad time trio, I do hope you enjoy this story and criticism is welcome ( I do not own Undertale, or RWBY, all ri...
Justice Reigns in our Stars, but the Nightmare is far from over by UTFAN360
Justice Reigns in our Stars, but t...by Undertale Fan For Life
Blue and Error were just having some time together in the Anti Void when they find an unlikely visitor....and he looks like Error! I don't own any of these characters
Hidden for so Long (Sans AU x Reader) {Remake} by RandomWriter-Chan
Hidden for so Long (Sans AU x Read...by Just Here & Thinking
Long ago, two races ruled the Earth: HUMANS and MONSTERS. One day, war broke out between the two races. After a long battle, the humans... wait no, the monsters were vic...
Growing up by MariaLNBorges
Growing upby MariaLNB
This story follows an emotionally and physically abused blue (swap sans) as he discovers solace in his new abilitys to travel the multiverse to get away from his current...
Smiling is a Coverup(Depressed Blueberry sans) by BruhItsUni
Smiling is a Coverup(Depressed Blu...by Elana Ruiz
Blue is always keeping himself busy, trying to run away from feelings he keeps catching on too. But it will always eat him up. He keeps acting weird and "not himsel...
Six Skeletons and The Waitress by ItsSwapPapyrus
Six Skeletons and The Waitressby Teutonic
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...
A Trio of Misfits | Bittybones story by Sabinarius
A Trio of Misfits | Bittybones sto...by Sabinarius
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...
Black Roses (Overprotective!Bad Guy Sans' x Child!Reader) by JulesRedenger
Black Roses (Overprotective!Bad Gu...by JulesRedenger
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...
Cock slut Error one shots.  by Loverofyaoi22
Cock slut Error one shots. by Loverofyaoi22
This is a collection of one shots where Error is a slut.
AU Undertale One-Shots 2 by DJWinterWolf
AU Undertale One-Shots 2by DJWinterWolf
Part 2 of AU Undertale One-Shots. I wright fluffy hurt/comfort oneshots. I do take request if I am able to do them. No lemons but there will be romace and small makeout...
A Skeleton's Hope (Undertale AU's x Reader) by Oh_Sweet_Chessus
A Skeleton's Hope (Undertale AU's...by Hi I’m dying inside
You've known Sans and Papyrus for four years, but all of a sudden they cut off all contact with you after two. You mainly ignored it until one day driving to their plac...
Sweet.Little.Unforgettable.Thing.  by balthazar5150
Sweet.Little.Unforgettable.Thing. by BabyYoda
Blue and lust becomes friends ...... Read to find out more
Criminal Conflict (an Undertale sanscest story) by __Purple_Fluffball__
Criminal Conflict (an Undertale sa...by Crossmare Slut
This is an Undertale book Criminals have always littered the streets causing a mess and breaking the law. But what happens when criminals Fall in Love? This includes all...
Six Skeletons, One Maid by RaccoonSinQueen
Six Skeletons, One Maidby RaccoonSinQueen
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...
Frans pictures by Ruby_Cat1082006
Frans picturesby Zhira
I found this pictures on deviantart,pinterest,google and Frans Amino
I accept.. Swadmare       (13+) by AUshipper321
I accept.. Swadmare (13+)by AUshipper321
so this is kinda killermare angst and Swadmare ship there's also kinda rape in it, if you don't like rape pls Don't read