Underswap Stories

1.2K Stories

Bone of Contention (Underswap Papyrus X Reader) by TheIndianaCrew
Bone of Contention (Underswap Papy...by Indiana
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...
You have become an Error (Discounted For Rewrite) by MikkiMausu
You have become an Error (Discount...by MikkiMausu
(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...
Keeping You Forever {YandereBlueberry x Reader} by AshiePear
Keeping You Forever {YandereBluebe...by Ash
You fall after being pushed of by the two people you thought that loved you, you thought that you would die. You wanted to die but not like this, ask you hit the floor e...
the unamused captive by Fandomfrenzy625
the unamused captiveby Fandomfrenzy625
being pulled away from your home while your simply enjoying some alone time can be annoying and to make it worse you have no say in the matter as 2 teams keep throwing...
Can I Stay? (Underswap!Sans × Reader) by Fruityyloopz
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...
My Light [Swap Papyrus x Depressed Reader] (DISCONTINUED) by Bears_Cave
My Light [Swap Papyrus x Depressed...by Bear
Your name is (y/n). Life has handed you a flaming bag of dog sh*t. It has ruined your life forever... or so you thought. At a young age, you weren't really paid much at...
Sans AUs x Reader: Boyfriend Scenarios by GameGeek03
Sans AUs x Reader: Boyfriend Scena...by Lune Moore
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...
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...
Undertale Boiz Oneshots by Fandomz_Fanboy
Undertale Boiz Oneshotsby Remus Hisahoshi
Yes , a sequel. I can't just leave everybody hanging when my oneshots were actually getting a fairly awesome amount of reads! Plus, I have even MORE ideas! I can't wait...
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...
Finding Fresh Air - Swap! Papyrus x Reader (DISCONTINUED) by B_string_e
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!** ...
Different Sans AUs getting sick because why not✨ by Yikes_Buddy
Different Sans AUs getting sick be...by Yikes.
(Updated) Heya buckaroozios, i made this like 2-3 years ago man, idk anymore but ill do my best to update it- for the 31-2 k of y'all still hangin onto this darned thing...
𝐞𝐭𝐡𝐞𝐫𝐢𝐚𝐥 ❪ au skeletons headcanons ❫ by -AINETHESCRIBE
𝐞𝐭𝐡𝐞𝐫𝐢𝐚𝐥 ❪ au skeletons he...by 𝐉𝐄𝐒𝐓𝐄𝐑
⤷ 𝖚𝖓𝖉𝖊𝖗𝖙𝖆𝖑𝖊 𝖆𝖚 𝖘𝖐𝖊𝖑𝖊𝖙𝖔𝖓𝖘 ! ❝ you're blue now! that's my special attack! ❞ ─── 𝘢 𝘧𝘦𝘸 𝘩𝘦𝘢𝘥𝘤𝘢𝘯𝘰𝘯𝘴 𝘧𝘰𝘳 𝘵𝘩𝘦 𝘢𝘶 𝘴𝘬𝘦𝘭𝘦𝘵𝘰𝘯𝘴...
My Anomaly (An Error Sans X Reader)  by nightmare597
My Anomaly (An Error Sans X Reader...by Nightmare
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...
Why all the Abuse? (An Underfell/Underswap AU) by Ramen-Sansy525
Why all the Abuse? (An Underfell/U...by Ramen-Sansy525
[^w^;] So... New description and cover art! Yay! Ok, let's go! "What's the point in existing, when you're worth nothing?" We all know that the Underfell...
Sans Aus x Reader Oneshots (Infrequent Updates) by good_night51
Sans Aus x Reader Oneshots (Infreq...by ᶜʰᵃʳˡᵒᵗᵗᵉ
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. ...
UnderTale Oneshots (FINISHED) by TheGrinningKitten
UnderTale Oneshots (FINISHED)by TheGrinningKitten
reincarnated as wyvern (atomictale sans[my au]) by CAMStheCATASAUR
reincarnated as wyvern (atomictale...by Charli Sanders
what if someone from our world died and was reincarnated as atomic!sans/wyvern? please understand that the au of 'atomictale' was made by me and i dont mind if anyone us...
The One Thing That They Care About (Sans AU x Reader x Papyrus AU) by TheiChronos
The One Thing That They Care About...by 𝐜𝐡𝐫𝐨𝐧𝐨𝐬, 𝐭. 𝐯.
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...
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...