1 - 20 of 3,146 Works in Alternate Universe - Underswap (Undertale)
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You, y/n, are a cat. You meet the Skeleton after an accident, and he looks like he's trapped. You're not sure, but will you become friends with him and turn things around for him?
But wait,why there are so many bones in here? -
"I'd Rather Do Normal "People" Things...Thanks!" by Cr8ter_Eight
Fandoms: Undertale (Video Game)
22 Dec 2025
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You are a Normal Person in pretty boring world.
You wake up.
Brush your teeth.
Comb your hair.
The same repetitive, insigniFi6@^t- th!^g every $ingle day....
One day, you do the same thing.
On that same day, you don't notice that an Insanely huge skeleton has tumbled out of your closet.Amazing.
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(New summary, i've also edited old chapters and added a new one)
To you, memory is a fickle concept.
A flowing river, in most cases. Slowly reaching new grounds. In some areas, the old stream grows thin, while in others, the water rapids reach incredible speeds.
That’s how you assume it is for others anyway.
While yours you imagine to be a pond. Fresh water newly formed from rain. No direction. No purpose. Only the clouds above know the truth. They know where your water came from. And sometimes, the water within reacts as if it remembers the riverbed once traveled…
At least, you would think so. If you didn't begin your sudden life and memories face planted in snow. Your only clue to who or where you are is a body wracked with pain (and injury), feeling of impending doom and ghostly sensation of deja vu. Oh! And the confusing knowledge of knowing a certain skeleton’s name, much to his displeasure.
OR
A story in which you meet wacky characters along the way of your universal travels. You’ll make enemies, you’ll make friends, maybe even….. more?
Though the worst part is that you can't stay still for long. Something is coming for you, and it won't stop until you’re dead. -
The Rehabilitation Center (or Dream's Worst Nightmare) by Miss_DeterminaForce
Fandoms: Undertale (Video Game)
22 Dec 2025
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“Oh, brother. I longed for your warmth, but all I obtained was the frozen feeling of indifference. If love cannot be reciprocated, could my hate still reach you ?”
In which Dream opens a medical center to help out insane people of the Multiverse. But insanity is often contagious. And with Nightmare's Gang in his hands, it couldn't get worse... Or so he thought.
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So....its been awhile....(three years) but who's counting? More for those who read Bittersweet Days (for the real ones who knew it as Inside Out, I fucking love you) this is for us.
You, yes you, are a deeply complex person. There is so much to you that has been shoved down under, because you have been shown time and time again that you are unlovable. But somewhere, that little kid in you, wants to prove that wrong. You just need help from the undead to help you grow, because even though life has shit on you time and time again, you have HOPE.
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Choose Your Fighter by FandomWorld9728
Fandoms: Undertale (Video Game), Mafiatale - Fandom, Mafiafell - Fandom, Mafiaswap - Fandom
21 Dec 2025
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When your life gets turned upside down, you move to a Monster run city to for a fresh start. Against your will, mind you. On your way to your new job, you get saved by some very interesting skeletons...
Series
- Part 18 of Undertales Across the Multiverse
- Part 12 of Sans/Reader Fics
- Part 13 of Papyrus/Reader Fics
- Part 8 of Reader Inserts
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The Serif household has been through many odd scenarios. After all, they are entirely comprised of other versions of the same two skeletons who got stuck in the world they have called home for six years, unable to return to their worlds and thus forced to carve out a life for themselves until further notice. All things considered, they found their stride and adapted to the ongoing weirdness of universe hopping.
That is, until she arrived. Flora, a woman so out of left field and disrupting their normality, appeared in the basement, battered and bloodied to hell and back. Stuck like all the others who had appeared before her, the Serif household is forced to accommodate her until she stabilizes, slowly beginning to get to know the lackluster and stone-faced woman who ensures they don't injure themselves via stupid means.
Few expect her to open up. Fewer expect her to accept becoming friends.
None expect for any of them to become much, much more.
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Soul's Delight by novarechive
Fandoms: Undertale (Video Game), Alternate Universe - Underswap (Undertale) - Fandom
20 Dec 2025
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At the age of 10, you didn’t expect your dreams to be confirmed with your soulmate tattoo.
‘WHAT’S THE SWEETEST THING YOU HAVE?’
Neither did you expect that the sweetest thing you'd ever get to have would be your future.
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Dream and Nightmare play tug-of-war with a god and everyone else gets dragged into it
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The Outer Realms by SarcosticSarcomere, TheDepressedJuggalette
Fandoms: Undertale (Video Game)
20 Dec 2025
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Written by: Ouija Board Demon the Depressed Juggalette and SarcosticSarcomere
The creators have just left en masse, leaving Ink in a pit of tension and apprehension. The multiverse is due for a change, but the answer as to what lies beyond familiarity and old bonds.
Out with the old, in with the new.
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A reader with many mental illnesses, has found themselves stuck with ten little dudes that need help just as much as they do. Going through the motions doesn’t cut it anymore, and life simply puts them deeper into the hole. Are these ten little dudes put together enough to help out this human, or will they get sucked into holes of their own? Is the reader put together enough to help themself and the others? Just found family-type story filled with bumps and potholes. Not my first story, but the first one on here.
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Diary of a Tired Afro-Latina who Decided to Date 14 Fuckass Skeletons at the Same Damn Time by BiblicalBeasts, sagemelons
Fandoms: Undertale (Video Game), Deltarune (Video Game)
18 Dec 2025
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When you agreed to move in with your datemates, you didn't think shit would be so damn chaotic. They argue over the dumbest shit and somehow manage to drag you into it?? Honestly, if the sex wasn't so good, you would've run for the hills already.
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This story explores how the multiverse changes when negativity finally outweighs positivity. It follows the multiverse, Nightmare's gang, and the way they are affected by these events. The tone is mostly dark, but there are moments of light along the way.
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A bitty reader goes on a crime-solving spree across the multiverse.
*You don’t have to read the previous fic to start here.
This is a continuation, but thanks to the amnesiac plotline, it should also work as a standalone.Series
- Part 3 of Avaverse
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Omniverse - Another forgotten one by Drifting with Cross (Underverse_writer)
Fandoms: Undertale (Video Game), UTMV, Undertale Multiverse - Fandom
16 Dec 2025
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Drifter's been to many universes before.
This one is no different.
Or is it...?
Little does Drifter know what she just got herself in...
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(Y/N) is just a normal girl. But when her normal life becomes a constant struggle going from one world to the next. Meeting different skeletons as she does so. Can she make it out of this cycle?
I have this story in Quotev and Wattpad too if you guys don't want to wait. I'm further ahead in that than in here.
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Echo had a plan. A really good one. Free Monster kind from the spell casted by humans. Find her sibling who disappeared. Then undo the curse placed on her. But when she suddenly gets transported to a house, and universe, full of skeletons. Looks like all plans are out the window at this point.
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You needed a new life for yourself.
So you move away from home and try your hand at a new city. Armed only with your things you brought and your partner in crime, Sheriff, your German Shepard.
You move into a new city full of monsters.
So what happens when you meet and connect with skeletons around town?
Well, guess you just gotta stick around to find out.
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The Time I Got Struck By Lightning and Got Hooked Up With Skeletons by SkellieUser666
Fandoms: Undertale (Video Game)
16 Dec 2025
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Your life was terrible. Terrible working conditions. Terrible fiancé. Terrible relationship with any and all people around you. The only good thing that happened to you was getting struck by lightening and waking up in a house full of skeletons.
Okay. Maybe not quite a good thing to happen now that you think about it.
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The House Next Door by BattleMaiden13
Fandoms: Undertale (Video Game), Underfell - Fandom, Underswap - Fandom, Swapfell - Fandom, Mafiatale - Fandom, Mafiafell - Fandom, Mafiaswap - Fandom
16 Dec 2025
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The first time you met monsters you manage to run into four of them and literally run into one of those four. Now they are apparently moving in next door with their siblings and you can't seem to imagine a life without monsters. On the plus side they tell horrible jokes and have endless amounts of energy. So what could possibly go wrong.
Part 1) Chapters 1-138
Part 2) Chapters 139 - ???