1 - 20 of 13,435 Works in Undertale Alternate Universes
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Storyshift Yellow: Guidebook by Jensk10
Fandoms: Undertale (Video Game), Undertale Yellow (Master Sword Video Game)
03 Nov 2025
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Summary
My take of SS Yellow based on SS by VoltraTheLively, where 12 roles are shifted around.
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Piecing Together The Pattern For A Stable Life by Streetlightgoblin
Fandoms: Undertale (Video Game)
03 Nov 2025
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Summary
Little by little, a new normal is established. Pieces fall into place, and aching souls begin to settle. All it takes is a little time.
Series
- Part 3 of Gathering loose threads
- Language:
- English
- Words:
- 6,337
- Chapters:
- 1/3
- Hits:
- 14
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Summary
A fic for ZeFanatic14 's supernatural Sans aus! Mostly Gabriel oriented.
- Language:
- English
- Words:
- 3,159
- Chapters:
- 1/?
- Kudos:
- 1
- Hits:
- 14
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Here Comes the Bride by FandomWorld9728
Fandoms: Undertale (Video Game), Underfell - Fandom, Underswap - Fandom, Swapfell red - Fandom, Fellswap Gold - Fandom, Horrortale - Fandom, Underlust - Fandom, Echotale - Fandom
03 Nov 2025
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Summary
You were so excited to finally get married to your long time fiancé, only for him to leave you for another girl with nothing but a note. Lucky for you, your two best friends were there to help you through this rough patch of your life.
Arc 1: Chapter 1 - 18
Arc 2: Chapter 19 - ?Series
- Part 12 of Undertales Across the Multiverse
- Part 8 of Papyrus/Reader Fics
- Part 8 of Sans/Reader Fics
- Part 1 of Here Comes the Bride
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Summary
Dust scared you. He scared you more than all the rest of his team put together. That being said, you were going to help him through this little mishap even if it killed you.
Series
- Part 2 of Turned Into An Animal (Sentence Prompts)
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Wrong Warp (pacifist route) by Pseudo_Inker
Fandoms: Undertale (Video Game), Super Mario & Related Fandoms, Sonic the Hedgehog - All Media Types, Kirby (Video Games), Minecraft (Video Game), Miitopia (Video Game), Bendy and the Ink Machine, Monster Hunter (Video Games), Pocket Monsters | Pokemon - All Media Types, Deltarune (Video Game), Five Nights at Freddy's, Terraria, Starbound (Video Game), Punch-Out!! (Video Games), Doki Doki Literature Club! (Visual Novel), Shovel Knight
03 Nov 2025
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Summary
An Undertale AU where the characters are replaced with characters from different video games, i only placed the major swaps of the AU in the character list as in only the characters that replaces the original undertale characters in this AU, Frisk & Papyrus & Alphys have been replaced with characters created by combining multiple characters, i will reveal who swaps with who as they come up in the story in the ends notes as i dont want to break the fourth wall in my story as some of the characters will already do so already themselves.
Series
- Part 1 of Mixed games AU bundle
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Summary
Dream and Nightmare take a moment to mourn something they never had.
Series
- Part 1 of Flowerverse
- Language:
- English
- Words:
- 508
- Chapters:
- 1/1
- Kudos:
- 1
- Hits:
- 22
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Summary
_.;⊛;._
Após serem trancafiados em um subsolo completamente desconhecido e repleto de mistérios e abismos perigosos, os monstros puderam finalmente sentir o gosto da paz. Porém, para os humanos, a herança da guerra se manteve e espalhou-se por toda a superfície, graças à ganância dos reis, trazendo morte e destruição para os mais fracos.Frisk, uma pobre criança assolada pela guerra em que nasceu, fora obrigada a fugir de seu vilarejo destruído para o Monte Ebott, mas, por causa de um descuido - ou talvez obra do destino-, teve sua história ligada às dos monstros e de seu passado.
Sua vida nas mãos daqueles que juraram vingança à sua espécie. Como tudo se desenrolará no fim?
_.;⊛;._
"✞⚐👍☜ ☠✌⚐ 🏱⚐👎☜ ☞🕆☝✋☼ 👎⚐ 💧☜🕆 👎☜💧❄✋☠⚐"
"Jamais..."Obs cronológica: Esse universo alternativo se passa antes de Lewstale (uma outra au minha) e os personagens que nela aparecem ainda não tiveram contato com nenhuma au.
_.;⊛;._
Universo alternativo de Undertale (by Toby Fox)
As capas dessa história, tal como a história em si é de minha autoria. Tenha uma boa leitura. :)
_.;⊛;._
- Language:
- Português brasileiro
- Words:
- 51,925
- Chapters:
- 4/11
- Hits:
- 20
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Summary
Only realizing the extent of Tenna's damage upon seeing it in the Light World, Susie, with some help from Kris, returns to the Dark World in an effort to fix him before it's too late—only to find it changed when they arrive.
Or: Susie's Chapter 3 Dark Fountain is TV World Underfell
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he said do with me what you want but please don't hurt my brother (please don't hurt yourself) by viktorforgets
Fandoms: Undertale (Video Game)
02 Nov 2025
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Summary
all monsters dust the same, guardians are not any different.
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october 17th : drug side effects & desperation
Series
- Part 4 of whumptober 2025
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Summary
Steve Jightmare finds himself a lovely goat lady to chat with.
- Language:
- English
- Words:
- 209
- Chapters:
- 1/1
- Collections:
- 1
- Hits:
- 5
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A Bad Choice For Hex by Anonymous
Fandoms: Five Nights at Freddy's, Undertale (Video Game)
02 Nov 2025
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Summary
Hexcode somehow gets convinced to work the Night Shift at Freddy's.
- Language:
- English
- Words:
- 276
- Chapters:
- 1/1
- Collections:
- 1
- Hits:
- 8
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Summary
LV Prey goes poking their head into the wrong timeline.
- Language:
- English
- Words:
- 603
- Chapters:
- 1/1
- Collections:
- 1
- Hits:
- 5
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[TIMELINES] In Services by Anonymous
Fandoms: Five Nights at Freddy's, Undertale (Video Game)
02 Nov 2025
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Summary
Timeline!Sans is looking for an expert in all the wrong places.
- Language:
- English
- Words:
- 244
- Chapters:
- 1/1
- Collections:
- 1
- Hits:
- 2
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Making A Monster by absurdmagewrites
Fandoms: Undertale (Video Game), Underfell-fandom, Underswap-Fandom, Swapfell-Fandom, Fellswap-Fandom, Fellswap Gold-Fandom, Horrortale-fandom, Crafttale-Fandom, Seaswap-Fandom
02 Nov 2025
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Summary
Sometimes life throws you a curveball. For you, your curveball was going to bed looking like a human, and waking up looking like a monster.
A skeleton monster to be precise.
With the barrier breaking, a large surge of magic descended on the town you live in, and transformed you overnight. Unsure what to do with you, and the others changed, you're ushered into a facility until a monster with similar magic can take you to teach you how to wield the now uncontrollable magic you've been given. After waiting in this place for four years, you'd given up hope that anyone would ever want to take you.
What a surprise for you when you find out that someone does. A lot of someones.
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Summary
You and your family are just enjoying a nice day at the park, when a life changing event happens that ruins everything.
You get taken away to a facility to be tested on...
Life doesn't feel as peaceful as it once did, you hated your new life.
"I wish I could just go into those story books I used to read..."
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Summary
AO3 description: Long ago, two races ruled over Earth: Humans and Monsters.
One day, war broke out between the two races
…
And that war won’t rest for you.
(Fellswap Gold story with some elements from Canon/Classic Underfell. Content for routes outside of the Closure Route [see: Underfell’s new routes, Closure is Pacifist] is unlikely.)Series
- Part 2 of Fizzyverse [UNDERTALE]
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Unavoidable Outcomes by Crystalight532
Fandoms: Undertale (Video Game), Undertale Yellow (Master Sword Video Game)
02 Nov 2025
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Summary
The Multiverse isn't as unreachable as one might think. Sometimes, all it takes is one aware person to tip the scales for another to find out about it. But when one isn't ready for it, returning to their own world is relieving and best for the psyche.
Humanity's thirst for knowledge is near insatiable. How far would they be willing to go to learn more about their new maical coinhabitants on the surface? How far would they go if they could weaponise their magic?
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Momento Mori (So Don't Fuck Life Up, You Don't Get A Second Chance.......Normally) by CrossoverAU
Fandoms: Undertale (Video Game)
02 Nov 2025
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Summary
Momento Mori- Latin for 'remember, you must die'
What is death, if not the end of one chapter, and the start of the next. Raine is dead. She wanted to be dead. She made her bed. Cleaned her room. Said her goodbyes. And tied the noose. When that didn't work, she slit her wrists. And when that didn't work, she took her grandfather's gun off the wall and shot herself in the head. That time, she finally did something right. Now she could sleep peacefully....
Why was she awake? She was definitely dead this time, why the hell was she awake?! And is that......Sans?! As in, Sans from Undertale?! As in the game that was one of her only reasons for not killing herself in high school?! That Undertale? That Sans? Why was he multiplying? And is that Papyrus?!
Death hurts. It causes pain to those around it even when it isn't attacking them. Then it comes for them next. If she wanted to get out of the Undertale world and back to her hopefully peaceful afterlife, she would need to show some bitches that before they bled out their marrow..... all over her damn floors?! Dammit Mutt, she just cleaned those!
Series
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Summary
You've been in The Void for so long that you can't recall anything. Then you find a way out in the form of a skeleton that uses the damn thing as an express highway. Well, sort of. Only he can see you. Your memories are being weird too, since everything seems so familiar even though you can't recall anything.
Then the human falls, and everything goes downhill.OC-centric fic written from second person, it's not all angst but there's basically no comfort for everything that goes wrong (at least at the story's current point). Arc 2 is multiverse stuff
Arc 1: Rock Bottom, 1-11
Arc 2: Funhouse Mirrors, 12-?