1 - 20 of 1,478 Works in Alternate Universe - Horrortale (Undertale)
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Red blares into your eyes as alarms scream, and wail into the air.
Their shrill shrieks mixing with your own wheezing breaths. Even as the helicopter sways precariously, the various vegetation its tangled in groaning and threatening to snap under the immense weight, you still can't find it in yourself to tear your eyes away from your pilot.
Or, rather, what remained of her.
The metal, having come flying off of Runner's copter and straight into yours, painting the cockpit in shades of red and grey, wasn't the only piece to crash through the windshield. But it was the one that did the most damage. Crashing through the window, and sending shards of glass directly into Strong's eyes, the metal had sliced... No, not sliced. That wasn't the right word.
The action was more akin to... To... It, fuck... Her face had the appearance of steak after you force a blunt blade through it; torn, with bits of fat hanging freely, and muscles shredded rather than cleanly cut... crushed bone and blood oozing from what had once been her jaw. The muscles and veins still spasmed and twitched, struggling to continue doing their job.
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On the day of their 13th birthday everyone has a name appear somewhere on their body. A script different than their own, but still familiar and comforting nonetheless. It's said to be your soulmates handwriting and, when you make physical contact for the first time, it's to change to the color or their eyes. Or so the rumor goes. But everyone knows that's just an old wives tale since finding yours is so far and few between.
But then there's Fanchon. What the hell is she supposed to do with 12 soulmates?? At least her odds are better than most...
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You were a normal human. You went to college, you had a life, friends, family, etc. Apparently, the void didn’t care much for happy endings, and you find yourself strapped to a table in an underground lab.
It’s fine, you have plot armor.
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Or, you get sucked into the void and your soul is placed in the body of eight-year-old Sans.
Arc 1: Heritage (1-7)
Arc 2: Hell (8-10)
Arc 3: Home (11-45)
Arc 4: Heart (46-59)
Arc 5: Hostage (60-?)Series
- Part 1 of How To Be A Human Being
- Part 1 of Hounds Of Love
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You should be dead. Everyone else in this god forsaken city died as soon as the barrier came down and these creatures, these MONSTERS, invaded Ebott City. You got lucky, or maybe not.
You had the bloodline of a mage. Which meant you could create barriers. In a moment of panic you had created a barrier in your apartment, locking you and your neighbor inside, and the monsters out.
But now the clock was ticking and you had a group of skeletons sniffing around your apartment, telling you that they couldn’t wait to drag you back to their den.
They meant as food…. r-right?
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The Void Mage and The Skeleton by transgirlnamedafterarock
Fandoms: Undertale (Video Game)
28 Sep 2025
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A number of years after Frisk leaves the underground a void mage living on Mount Ebott stumbles i̶n̶t̶o̶ upon a entrance to the underground searching for magical materials. Various encounters and violent realizations occur as she makes her way through the underground doing her best to save everyone she can. Forced to accept the truth that things are much worse for monster kind than ever before, she will do everything to save a people from extinction. Can she do what she needs to in time? Or will she be forced to come to the conclusion that its much to late for anything to be done.
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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
28 Sep 2025
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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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The House Next Door by BattleMaiden13
Fandoms: Undertale (Video Game), Underfell - Fandom, Underswap - Fandom, Swapfell - Fandom, Mafiatale - Fandom, Mafiafell - Fandom, Mafiaswap - Fandom
28 Sep 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 - ??? -
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Instead of another skeleton group coming out of the machine, it was you. A teenage girl. Now they have to figure out what went wrong and why this happened. In the meantime, they have their own puzzle and yours to solve in order to adjust to what seems like their new lives.
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A random teenage girl came in through the machine and now they have to deal with that and their own issues.
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You fell into the Underground years ago. Being a part of society as an adult with a job to maintain was hard enough as is, but the gold-toothed skeleton and his tyrant of a brother that tormented you made shit a lot more difficult.
See, that was hell; but now you're working for an oozing, skele-octopus creature who's got a thing for negativity. You aren't sure if this situation is better or worse, but considering you're being forced to work closely with Sans, it's probably worse.
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These are a series of short stories with variants of Sans from different AUs for a potential bigger fanfiction I wanna write in the future.
In these stories, Reader is Gender Neutral and is Referred to as Yin(short for Y/n for convince). I will NEVER describe the Reader or their appearance, there may be times where I have the reader wear clothing and describe it, but it will not be very often so you are free to imagine any outfit in these scenarios that fit with the setting. For certain Sans AUs, I may make you shorter or taller based off my own headcanons for how tall characters are, but that is as far as it will be. For Oneshots with sex or similar stuff, gender neutral terms and compliments will remain as well, but I will write separate sections for those that have either parts.
Terms of endearment will be gender neutral, compliments will not fully describe your appearance, etc. I WANT THESE STORIES TO BE ABLE TO BE ENJOYED BY PEOPLE OF ALL SHAPES, SIZES, ETC. IF YOU FEEL SOMETHING COULD BE BETTER, LET ME KNOW IN COMMENTS HOW YOU FEEL AND FOR CONSTRUCTIVE CRITICISM. THAT IS ALL, THANK YOU FOR READING AHEAD!
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You’re a scientist! Yes you! And you’re going on a trip through the multiverse! Dw, you did it on purpose
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It was all great. You had friends, family, a place to call home. Until the Human child fell and ruined everything. Now? There’s nothing left but a desolate Underground for you and your Husband to be reminded of the past.
That is until the ground breaks from under you and spits you and your husband into another universe entirely.
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breaking the confines of platonic ideology by helio_heliohelio
Fandoms: Undertale (Video Game)
24 Sep 2025
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With the ascension of monsters, there hasn't been a boring day since. Living in a town close to the mountain range had its perks, and things certainly changed when the neighbourhood I lived in starts getting new residents.
The only problem now is finding a better job.
Luckily, a skeleton appears and tells me about a restaurant I can work at. I accept.
And I soon run into a whole bunch of other skeletons that all seem to like me.
Romantically, and I'm afraid of what will happen. -
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Life sucked, that's how all these start out, right? well they are true. life fucks you over, and just as you get back on your feet will do it again.
you loose your job, your apartment, and your fiancé cheats on you constantly. you say fuck it all and go to the safest bar for any woman to get smashed on magical alcohol.you didn't know you'd end up sleeping with your new boss before you even were hired. or applied for it, but fuck it paid good.
(this is based of a kinktober one shot, you will get to suggest what you want to happen when i ask in the end notes! so please keep an eye out.)
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How many times can one die before they snap? How much suffering can they take? Aliza takes a little inspiration upon from her last conversation with Sans.
If Horrortale had a genocide route basically.
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Exhaustion makes his steps heavier, as he travels a route he knows by soul. It isn’t long before Sans is lulled to sleep. It isn’t long before Sans begins to dream.
Deep within this cold, hungry sleep, Sans finds that his shadow has a story to tell.
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Horror meets Nightmare for the first time.
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You were finally getting your life back on track. Juggling college courses and a new job, you were slowly but surely rebuilding from the ground up, convinced the worst was behind you. That all changes when a magical summons you can't refuse rips you from your world and drops you into a house filled with powerful, skeletal monsters who despise you before you’ve even said a word.
To them, you are the arrogant and careless human who shattered the soul of their dearest friend, the gentle mage Lyra. They see you not as a person, but as a living tool—a magical "key" they require to heal the damage you supposedly caused. Trapped in a multiversal nexus with no way home, you must navigate a gauntlet of relentless animosity and suspicion.
Every word you say is twisted, every action is judged through the lens of lies you don't even know have been told. How can you survive in a home that isn't a home, surrounded by enemies who believe they are the heroes? And how can you prove your innocence when the true manipulator is the very person they've sworn to protect?
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"It had been a few days since Aliza had seen Sans, and as she'd come to learn, that was never a good thing."
After completing Papyrus' fifth puzzle, Aliza was just trying to get used to living with the skeleton brothers and keeping herself alive in a world that wanted just the opposite. Every action had its corresponding consequence, and Aliza certainly wasn't expecting to find tentative allies in Sans and Papyrus, especially not when relations with Queen Undyne and the state of the Core kept getting continuously worse.
Nevertheless, it seemed a small gift, a little understanding, and a lot of empathy on her part went a long ways when it came to a Monster as confusing as Sans.
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I know you've been avoiding me. by Joelmillerismysugardaddy2009
Fandoms: Undertale (Video Game)
21 Sep 2025
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Basically little info in alizas life if she was stuck still underground - she's 16 at this point.
- Language:
- English
- Words:
- 679
- Chapters:
- 1/1
- Hits:
- 9
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It's been 8 months since your younger sister went missing, worried you decide to go looking.
Your older sibling seems to know something but is dodging the question, what do they know?Last you heard Aliza was headed up Mt. Ebott, you hope to find her before it's too late.
Maybe you should have packed more medication than previously thought. You just hope you'll hurry before something goes wrong.