Underswap Stories

1.2K Stories

Can I Stay? (Underswap!Sans × Reader) by Fruityyloopz
#1
Can I Stay? (Underswap!Sans × Read...by Justmonika
[Prolong] My name is (Y/N). I have experienced many resets, so many I have lost count. The only people who remember are Sans, Flowey, and me. The monsters down here are...
It's A Beautiful Day || Undertale AUs by Firestorm174ga
#2
It's A Beautiful Day || Undertale...by Firestorm174ga
It was a beautiful day, a Friday, and two writers with too much time and way too much energy plunked down Error and Blue into a new Multiverse. Dreamswap, to be precise...
Becoming an error by KarmaAkabane425
#3
Becoming an errorby Karma Akabane
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
Naturetale : reborn as lavender  by KarmaAkabane425
#4
Naturetale : reborn as lavender by Karma Akabane
(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...
Bitter Berries by PonchoBow
#5
Bitter Berriesby 𝕂𝕒𝕔𝕙𝕠𝕨
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...
I'm...swap gaster? by KarmaAkabane425
#6
I'm...swap gaster?by Karma Akabane
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...
Home (Undertale Machine AU) by DeadEnDead
#7
Home (Undertale Machine AU)by DeadEnDead
Right before being completely destroyed, the machine pulls through a lone papyrus called Wick. Struggling with memory loss, trauma and disability, Wick learns to find ho...
Finding Fresh Air - Swap! Papyrus x Reader (Rewrite in progress) by B_string_e
#9
Finding Fresh Air - Swap! Papyrus...by B_string_e
!! Long Chapters !! 1000-4000 words each! **This book will be continued by another person so check the A/n at the end of the book to go to their continuation of this!** ...
Completed
An Underswap AU: A Tale of Seven Book 1 by sabermoonlight1616
#10
An Underswap AU: A Tale of Seven B...by [REDACTED]
The Multiverse is vast, expanding continuously as more alternate dimensions are being created. Each world possesses it's own unique laws, stories and inhabitants. This w...
Light or dark? Bad sanses x child reader by Raining-3lsewhere
#11
Light or dark? Bad sanses x child...by Leah ☔︎︎
Y/n was and/or is a very sweet child, unfortunately for them they weren't treated very well by their mother or father, Y/n was abused and didn't have anyone. Fortunately...
Completed
Black Roses (Overprotective!Bad Guy Sans' x Child!Reader) by JulesRedenger
#12
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...
Completed
Transported as nightmare from momma Cq!?  by KarmaAkabane425
#13
Transported as nightmare from momm...by Karma Akabane
What if someone from our world was transported into momma Cq as nightmare? What if a bit later after being nightmare for a while, he finds the momma Cq version of nughtm...
Voodoo (Errorberry) by SpiritWolfNura
#14
Voodoo (Errorberry)by Kyran Wolfe
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...
Completed
The Life of Blueberry - (An Underswap Story) by BloodGumm
#15
The Life of Blueberry - (An Unders...by Samantha Stilger
Blueberry - Sans of Underswap. But is he so different from Undertale Sans? Find out as we view Blueberry Sans' life in the Underground. I don't know what rating is used...
Completed
Reborn as fellswap san and now I'm kinda blind!? by KarmaAkabane425
#16
Reborn as fellswap san and now I'm...by Karma Akabane
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...
Frans pictures by Ruby_Cat1082006
#17
Frans picturesby Zhira
I found this pictures on deviantart,pinterest,google and Frans Amino
Karmatic Trio (Bad time trio x BNHA)  by DontAskImN0body
#18
Karmatic Trio (Bad time trio x BNH...by ImN0body
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...
Reborn as sans from UnderSoul  by KarmaAkabane425
#19
Reborn as sans from UnderSoul by Karma Akabane
I was reborn as sans from my own made up au. How did that happen? I have no idea. Luckily I was still a kid so I didn't have to act like how I made sans to act like but...
Becoming papyrus from underswap  by KarmaAkabane425
#20
Becoming papyrus from underswap by Karma Akabane
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...