Underswap Stories

1.2K Stories

Unexpected Helper (Nightberry) by SpiritWolfNura
Unexpected Helper (Nightberry)by Kyran Wolfe
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...
SAFE Home (Sans AU's X Reader X Papyrus AU's) by EmelinStriker
SAFE Home (Sans AU's X Reader X Pa...by Emelin
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...
Reincarnated as Underswap Sans and how about Error get kidnapped instead? by SkeleSheena
Reincarnated as Underswap Sans and...by SkeleSheena
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...
Villainess with a death wish - AU Sans x reader x AU Papyrus by Mallory_Abi_Moriarty
Villainess with a death wish - AU...by Mallory_Abi_Moriarty
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...
Naturetale : reborn as lavender  by KarmaAkabane425
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...
Dream x Blue Oneshots by FallenAsleepYetAgain
Dream x Blue Oneshotsby FallenAsleepYetAgain
Fun Fact - Dream/Blue is my comfort ship, and they deserve a book all to themselves. Art is by Mega-Loser-0 on Tumblr.
Undertale Au Daughter Scenarios  by Mugmaya156
Undertale Au Daughter Scenarios by IidaSimp_17
I wanted to try it out do why not?
US sans x UF grillby (COMPLETED!) by DreamEaterArts
US sans x UF grillby (COMPLETED!)by marirco lovelancia
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...
Reborn as the tree of feelings by KarmaAkabane425
Reborn as the tree of feelingsby Karma Akabane
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...
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...
Nightberry (Nightmare x Blueberry) by PrismarinePalace
Nightberry (Nightmare x Blueberry)by ShinyCrow
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...
AU Sans x Reader Oneshots by MorningSweets
AU Sans x Reader Oneshotsby {sweets}
**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...
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...
Bone of Contention (Underswap Papyrus X Reader) by TheIndianaCrew
Bone of Contention (Underswap Papy...by Indie
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...
Game Of House by ican_english
Game Of Houseby Frick.
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...
Voodoo (Errorberry) by SpiritWolfNura
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...
Reborn in an undertale au as a siren by KarmaAkabane425
Reborn in an undertale au as a sir...by Karma Akabane
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...
𝐊𝐢𝐜𝐤 𝐄'𝐦 𝐓𝐨 𝐓𝐡𝐞 𝐂𝐮𝐫𝐯𝐞  by AngelGotchiX2X
𝐊𝐢𝐜𝐤 𝐄'𝐦 𝐓𝐨 𝐓𝐡𝐞 𝐂𝐮𝐫�...by Levi
[𝐀𝐔𝐒 𝐗 𝐑𝐄𝐀𝐃𝐄𝐑] "𝙸𝚏 𝚢𝚘𝚞 𝚝𝚊𝚕𝚔 𝚝𝚘 𝚖𝚎, 𝙸 𝚌𝚊𝚗 𝚑𝚎𝚕𝚙 𝚢𝚘𝚞" --------------------------------------------♡♡♡♡♡♡ ♡One moment she was sle...
I Got Reincarnated...great by ValentineLockheart
I Got Reincarnated...greatby Valentine Lockheart
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...
Undertale x male reader by RandomKid362
Undertale x male readerby Toad Yeager
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...