1 - 20 of 805 Works in Swapfell Sans (Undertale)

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  1. Tags
    Summary

    Spending time with your beloved royals guards and advisors was always the fondest moment of your day. You loved them all, they were your home.

    This was a dream you hoped would never end.

    You could have never predicted what would come of this dream, and how quickly it would shatter.

    Nicknames for clarity:

    UT Sans: Sans
    UT Paps: Papyrus

    US Sans: Blue
    US Paps: Stretch

    UF Sans: Red
    UF Paps: Edge

    SF Sans: Nox
    SF Paps: Mutt

    Language:
    English
    Words:
    11,937
    Chapters:
    5/?
    Comments:
    44
    Kudos:
    119
    Bookmarks:
    24
    Hits:
    1,572
  2. Tags
    Summary

    Red gets out of prison after doing federal time. And with his freedom he is ready to get back out into the world and get his revenge. There's a lot going on and he just has have his hands in it especially if it leads him back to the snitch that got him locked up.

    There is no SansXReader in this one. And I will explain why in the story so if you don't like that particular style of writing you may go past this. But if that doesn't bother you, welcome come on in, I hope you enjoy this debauchery.

    Language:
    English
    Words:
    148,085
    Chapters:
    28/?
    Comments:
    20
    Kudos:
    24
    Bookmarks:
    6
    Hits:
    1,391
  3. Tags
    Summary

    Monsters have come to the surface, and with that a lot of probelms have been caused, so maybe a marriage between two people from the two races might help?

    Language:
    English
    Words:
    67,316
    Chapters:
    39/?
    Comments:
    554
    Kudos:
    469
    Bookmarks:
    81
    Hits:
    14,342
  4. Tags
    Summary

    Sans tries to fix his mistake, and bring all his versions back to thier own worlds. But working hard together with Stretch they yet again bring somone to thier world another fail attempt. But there was somting different, it wasnt versions off them and it was just one skeleton who been brough up here. They have a nickname and they always act odd and always have a pocker face. Just not really reacting when they should react...

    (somties gonna be added lil drawings for the story)

    Language:
    English
    Words:
    27,417
    Chapters:
    3/?
    Comments:
    2
    Kudos:
    11
    Bookmarks:
    5
    Hits:
    251
  5. Tags
    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.

    Language:
    English
    Words:
    633,429
    Chapters:
    81/?
    Comments:
    4,256
    Kudos:
    4,421
    Bookmarks:
    1,003
    Hits:
    248,321
  6. Tags
    Summary

    You are a lonely woman in a time of railroad expansions, stagecoaches, pioneers, cowboys, prospectors, and monsters out west. Literal monsters from the territory of Ebbott. You have a penpal from the desert part of Ebbott out west. Lady Toriel and you have been speaking with her since her last plea for better human and monster relations. You are on your way to meet your new friend and teacher with the high hopes that you will make a difference. You didn't have much other than the passion to help bridge the gap between everyone. Toriel would be giving you a job as her partner. You can't wait... however you come across a bunch of centaurs, with upper bodies of skeletons, that may or may not be up to no good.

    Language:
    English
    Words:
    18,045
    Chapters:
    5/?
    Comments:
    27
    Kudos:
    155
    Bookmarks:
    37
    Hits:
    1,782
  7. Tags
    Summary

    Being turned into a monster as a teenager, growing up in labs and behind locked doors, Lark gets a new chance at life when monsters take over the care of "Mutatios" and he finds himself taken in by a big family of brothers. Skeleton brothers.

    They all freak him out.

    Language:
    English
    Words:
    46,848
    Chapters:
    6/?
    Collections:
    1
    Comments:
    16
    Kudos:
    40
    Bookmarks:
    12
    Hits:
    815
  8. Tags
    Summary

    Bill and Nightmare make an alliance, with Bill helping Nightmare form his gang and defeat the Star Sanses, and Nightmare helping Bill get a Multiversal Rift from Ink. Nightmare recruits his gang, Bill helping get him started with the Murder Time Trio, before Nightmare starts finding recruits on his own. Nightmare's Gang is impossibly chaotic, and so are the Star Sanses honestly. Summary will probably be updated at some point in the future.

    All chapters have been revised as of 2/6/2025, or 35/?

    Discord server: https://discord.gg/wQfvxyEuvj

    Tumblr in case you guys want to make fanart:https://www.tumblr.com/werecat1234

    Cover picture https://www.tumblr.com/werecat1234/766504234727489536/new-cover-for-multiverse-madness?source=share

    Series
    Language:
    English
    Words:
    404,904
    Chapters:
    70/70
    Comments:
    442
    Kudos:
    317
    Bookmarks:
    27
    Hits:
    8,838
  9. Tags
    Summary

    Monsters and humans were now part of the same, messy, society. And you have a tendency to make things difficult for yourself.

    Or

    A human adopted a monster child and numerous skeletons fall for the mess that they are.

    Language:
    English
    Words:
    2,706
    Chapters:
    2/?
    Comments:
    20
    Kudos:
    208
    Bookmarks:
    45
    Hits:
    1,929
  10. Tags
    Summary

    You are getting set up to go to the University of your dreams but sadly the dorm life isn't what you'd like for studying... so you go looking for an affordable place to stay. Finding an ad in the paper for everything you could want in a place only set back is they are looking for male applicants only... oh and the other tenants are monsters not that you mind. Maybe if you could go in person you can plead your case and oh my goodness they're all skeletons.

    Series
    Language:
    English
    Words:
    117,706
    Chapters:
    24/?
    Collections:
    1
    Comments:
    613
    Kudos:
    2,678
    Bookmarks:
    541
    Hits:
    81,085
  11. Tags
    Summary

    You're an SSS ranked hunter who fights demonic beasts for a living and hangs with your cool roommates in your free time.

    Sans is your average skeleton - just trying to figure out how to stop dungeon bursts from wreaking havoc on the city when he manages to land you, Papyrus and himself in an alternate universe. But there's still room for things to get stranger in the house of mirrors the three of you are starting to call home.

    Language:
    English
    Words:
    4,023
    Chapters:
    2/?
    Comments:
    7
    Kudos:
    20
    Bookmarks:
    8
    Hits:
    287
  12. Tags
    Summary

    During a time that bitties have been bred with even human killing abilities in illegal kennels for bitty fights. Bitties are still not considered people or even regular monsters...just things or pets in the eyes of the law. One night you managed to save the life of a helpless edgy bitty from a blackberry bitty named Pitch and his gang. By saving the poor Edgy and finding out just how many problems he had to cause him to be in such a situation to begin with led you to the life you have now. You've become a licensed bitty therapist in hopes of reaching out to the abused, the neglected, and street worn bitties and giving them a chance at a better life. With your supportive and loving edgy bitty by your side years later down the road you should have know that eventually the past would come back to claim you after all your life no longer belongs to you.

    Series
    Language:
    English
    Words:
    62,283
    Chapters:
    12/?
    Comments:
    161
    Kudos:
    688
    Bookmarks:
    123
    Hits:
    13,634
  13. Tags
    Summary

    The Skelton sub-species is dying out in every universe.
    Gaster is worried about that and decided to do something about it.

     

     

    (Should I be making a new skeleton reader story...no.
    Am I going to anyway...yes.)

    Inspired by Making a Monster by absurdmagewrites

    and my own fic, I'm No Human.

    Series
    Language:
    English
    Words:
    22,813
    Chapters:
    9/?
    Comments:
    176
    Kudos:
    959
    Bookmarks:
    217
    Hits:
    16,493
  14. Tags
    Summary

    It has been a year since the car crash that suddenly and drastically threw Rowan’s world into disarray. She’s finally, more or less, put the pieces of her life back together. Then a rather charming skeleton family moves in across the street. Undecided pairings - though likely many in related and unrelated chapters. Admitted bias for Red and Nox. Writing what I feel like, to be honest. So going to be very character-interaction driven with lots of fluff. …And probably smut (separated out if that's the case). Inspired by, and the first chapter just steals from, the Bonely Hearts Club’s original demo. Characterizations (especially Nox and Rus) are also influenced by “popatochisp”, amongst other authors. The world is on fire and I need feels-goods (also known as dopamine) damn it.

    Language:
    English
    Words:
    10,405
    Chapters:
    2/?
    Kudos:
    3
    Hits:
    37
  15. Tags
    Summary

    Hello, my name is Mazy, now that you will be a reader soon, you are known as a Mazyville, I'm nonbinary and go by they/them. My favorite fandom is Undertale and its alternative universes. I write semi-literate so all can understand well. English isn't my first language, though, so don't be too bitter.

    I'm not a new writer, but I've never written on AO3 before. I'll be taking requests for any fanfiction Idea you have, not a short, but I'll make a not-so-long story about it. Just comment with your main idea or a summary of what you want your story to be, it can be ANYthing and ANY ship.

    READ THE REST OF IT TO FIND OUT MORE!! AND READ THE NOTES!!!

    Language:
    English
    Words:
    317
    Chapters:
    1/1
    Comments:
    10
    Kudos:
    3
    Bookmarks:
    1
    Hits:
    213
  16. Tags
    Summary

    Life hates me, and so that's why I hate life back. Some people will say it's just satisfaction to do so, or some sort of mentality of: you hate me, I'll hate you back.

    But no.

    Not for me.

    For me, it's the line between life and death. A rule I must follow because...

    Nothing will ever go right for me, no matter how evil or heroic I be.

    or

    What happens if I replaced Y/n with Delta, my demon oc? How would the world of Zombietale change?

    or

    Delta is trapped by a facility that promises to make a cure. Spoiler alert: They didn't. Delta decided to escaped for good, only to meet skeletons three years later.

    --
    Check out the first chapter for background information
    --
    Hello! So you know me by now. If ya haven't already I highly recommend reading Kamisori's story Zombietale. Even if the story and plots are completely different maybe you can get some sense of (a few) of the character's personalities.

    Zombietale is a really good fic! I love it!
    --
    11/? - First chapter doesn't count

    (Zombietale belongs to Kamisori)
    (Writing belongs to me (Me Paina))
    (Drawing belongs to me (Me Paina))
    (Undertale belongs to Toby Fox)

    Language:
    English
    Words:
    30,649
    Chapters:
    12/?
    Comments:
    15
    Kudos:
    49
    Bookmarks:
    11
    Hits:
    3,645
  17. Tags
    Summary

    Stretch, and Money have been best friends from the moment they met. They just understood one another completely, but now are they something more? When a small twist is thrown into their lives, will they be able to cope, and end up happy together, or crash, and burn?

    Language:
    English
    Words:
    65,094
    Chapters:
    12/?
    Comments:
    154
    Kudos:
    260
    Bookmarks:
    51
    Hits:
    5,743
  18. Tags
    Summary

    Y/N is living a normal day to day life, rehearsals in the morning, and bar maid at night. Until one day, she gets a new security guard at the ebbot theatre, named sans. He seems sweet enough, and on top of that, he's a monster skeleton. What's not to love about monsters! But when y/n starts seeing him and his brother at her bar and out in the street wearing different clothes acting different, she starts to get freaked out, not only that she starts getting pounding headaches, seeing things that didn't happen to her but also it did happen to her just not in this timeline. She's confused and disoriented, and days feel like they drag and drag, never ending. She can't sleep, she can't eat. So she asks sans for his help, but now she's being dragged further into the deep end. How long can she handle it till she drowns or is pulled back out ?

    Language:
    English
    Words:
    1,363
    Chapters:
    1/1
    Comments:
    1
    Kudos:
    4
    Bookmarks:
    2
    Hits:
    97
  19. Tags
    Summary

    Razz, the young Prince of the Fell Kingdom, embarks on a transformative journey as he marries Sheikh Honey of the Tale Kingdom. This union, forged through necessity and sealed with magic, marks Razz's transition into adulthood. As he navigates his new life, he grapples with the complexities of being the second wife to Honey, sharing his affections with the enigmatic first wife, Sans. Their initial interactions are fraught with tension and misunderstandings, as Razz strives to forge a bond with Sans amidst the challenges of his newfound role.

    Series
    Language:
    English
    Words:
    9,547
    Chapters:
    2/4
    Comments:
    2
    Kudos:
    2
    Hits:
    47
  20. Tags
    Summary

    (y/n) is your average; "ima do my own thing while the world burns " type of person... or is she ?

    enjoy as she deals with the struggles living with people who cant make their minds about their opinions of her !

    who knows it might get good(?)

    (ill probably write a better summery later on)

    Language:
    English
    Words:
    23,058
    Chapters:
    18/?
    Comments:
    32
    Kudos:
    146
    Bookmarks:
    28
    Hits:
    2,581

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