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  • Time Miscalculation
    74.1K 2.9K 15

    After waking up in a 10 year-old body (with all his previous injuries), Error tries to figure out how it all led to that point. He didn't know where he was, he's not completely sure how he got there, and his memories were fragmented. Being taken in by the Gaster of that AU and finding out that his codes are integrated...

    Mature
  • Restart Malfunction - HoneyMustard
    9.5K 339 9

    With the resets jumping back and forth, it seems to simply set the same path once more. However, this pattern breaks when the code seems to restart - and this time, there are a few more unfamiliar changes. How will Red react to the new MERCY filled Papyrus? And how will Honey adapt to the brother he loved continuously...

  • Games [Fell!Sans x Reader]
    3.1K 107 9

    Your fist clenched, unsure if you should punch the living daylight out of him, "Who said I was playing your game." "you don't have to say anything, you're automatically playing," He took a step back and walked past you with a lazy wink. "but at the end of every game, i always win. and you better believe it, sweetheart...

  • The glitch, and the blot. {Sorta Errink}
    10.6K 290 89

    Ink wants to create Error wants to destroy But they need to get to know eachother to figure out... That Ink needs a friend And Error needs help

  • An Undertale Ninja Turtles Crossover
    17.7K 413 8

    (Y/N) (L/N) has moved to NYC with her new siblings Asriel, Frisk, and Chara Dreemurr along with Sans. Little did they know they will be getting one shell shocking news, New friends to meet, new foes to fight, old friends to see, and old foes meet. Betrayal and Hate will rise. What path will they take? What path will Y...

  • *Rewrite/New Version* Healing What Has Been Broken
    90.6K 3.6K 11

    (This is the rewrite/newer version of 'Healing What Has Been Broken'. I do not own Undertale, the characters, or the cover - they belong to their respectful owners and JuneTheTrickster made the art based off of my new design for Erratum. I only own my versions of the characters, OC's, and this story.) Error, the Force...

    Mature
  • Rescue (UnderFell!Sans X Reader Fanfiction)
    76.3K 3.2K 32

    It was supposed to be a search and rescue with your two closest friends. With your 'brother' Frisk missing now two days and that foster home giving less than a damn, it was up to you and your best friends to follow his one clue. But what happens when one little clue leads to a situation larger than life? Will you surv...

  • Lost And Found~ MafiaTale Fanfic
    158K 6.4K 20

    In the business of human trafficking, mercy isn't a well known word. You and your crate mate, a child named Frisk, are obidiently waiting to be released to a 'master' when havoc breaks out around you. Guns are fired and you're doing your best to protect Frisk when your crate is pried open by unfamiliar faces. How will...

    Completed  
  • Mafiatale Sans x female reader (Possession)
    79.4K 2.2K 36

    Over thousands of years the Underground's hopes of becoming free had slowly disappeared and have gone to alternative motives: Money, sex and power. A human soul these days has become almost priceless with very notorious gang members and it just so happens their luck has just rolled in. Not only a human has strolled in...

    Completed  
  • Cryophobia - (Sans x Reader)
    1M 41.8K 24

    Next person to comment on this monstrosity gets fucking vored!! × ❝You made your choice a long time ago.❞

    Completed  
  • Crime (A multiship story)
    72.9K 3.2K 25

    Cross, Reaper, Horror, Killer, Error and Dust are criminals, constantly on the run. They stay on one city then are forced to run to another city once the police find out about them. They're soon forced to flee to a city named Ebott. The city is named after the mountain, and is famous for both the mountain and it's co...

  • Something More (Ink x Error)
    218K 7.9K 36

    Ink is a protector Error is a destroyer Naturally, they don't get along , but maybe time can change that Maybe they can be something more than enemies in the future.... (This Book Is NOT On Hiatus, I'm Just A Slow Writer) (I do not own Ink or Error. Ink belongs to Comyet and Error belongs to loverofpiggies. You can...

  • UpperFell
    5.7K 232 19

    Sans, or Red as he prefers, is the lowest of the low in Ebott City. He does odd jobs around the city for quick cash, that is until he meets Papyrus. Papyrus is lonely and "spoilt brat" (in Reds words) who is willing to pay Red to spend time with him, much to Reds reluctantly at first. [Papyrus is a human with magic an...

    Mature
  • Lust [Sans X Papyrus] -UnderFell Fontcest-
    17.8K 311 9

    . It's the year 20--, Monsters, Humans, and other fantasy creatures have lived with eachother for many many years, but there is quite a bit of discrimination. This story focuses on Sans, a skeleton who prefers to be called Red, and he isn't very nice. He has many hidden talents, some of which another characte...

  • Healing *Discontinued For Now*
    58.5K 1.8K 15

    Sans (Red) is a monster trapped in the nightmare that is Underfell. Brotherly abuse and the stresses of this world cause him to do the unthinkable, how will the Swap brothers react to the arrival of his broken mind? Possible trigger warnings? I don't know, read at your own risk. UnderFell and by extension Undertale do...

  • (Underfell sans x reader (female)) UNDERCOVER
    492K 17.3K 64

    You're a human that has fallen into Mt. Ebott on the year where all humans dress as monsters...Halloween. So how will the monsters know if you're a human or not?

    Completed  
  • HM/EB: Forgiveness and Sacrifice
    32.3K 1K 15

    Sans has been beat and tortured for most of his miserable life, almost exclusively by his younger brother, Papyrus. But, what happens when Sans is ripped from what he knows? How will Papyrus react? And, more importantly, where will Sans end up? Papyrus has abused and belittled his brother for the majority of his life...

    Completed   Mature
  • Bone of Contention (Underswap Papyrus X Reader)
    369K 14.6K 62

    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 they came from. Then, there are those like you who don't quite know what to think yet. What will happen once you become acquainted with two skeleton b...

  • I Fell In Love...With You? (Sans x Monster Reader)
    19K 418 15

    (Y/N) had always been a rebel. She was the only monster to live on the surface after the war. When suddenly her own kind returns, she gets jealous of them sharing her sunlight. What happens when she has an unfriendly run in with two strange skeletons?

    Completed  
  • Above ground (Sans x reader) ~Sequel~
    83.8K 3K 27

    So this is a sequel to a story I wrote a while ago. It's called: A whole new experience (Sans x reader). You should probably read that before you dive into this emotional rollercoaster. I mean, it's not like I can stop you. Just saying. If you want to read that story first you can look it up on my profile or type: A w...

    Completed   Mature
  • Underverse High (AU Sans x reader)
    42.3K 771 34

    (Inspired by HayumiJuno. You should go check her out she's pretty cool.) You lived alone, you never really had any friends at your school, in fact everyone thought you were creepy and weird. That is until your teacher Toriel enrolls you to a new Highschool. Where weird is normal and normal is weird

  • Undertale Sans x werewolf reader
    46.8K 1.1K 41

    Y/n is an average girl! ok, I lied... she's not that average, she's a girl who can turn into a wolf. she's in deep trouble but is caught and thrown down into Mt Ebbott.

  • Goodnight, Kiddo... (Adopted by Sans! Reader Fanfic)
    27.7K 794 15

    You are an orphan, abandoned by your parents at birth. You've lived between countless foster families and a dreaded girl's home for as long as you can remember, because nobody chose to adopt you. Now, you are fifteen years old, and you decide to run away. Monsters have been living on the surface come four years now...

    Completed  
  • Kind Of Comical [Sans X Reader]
    217K 7.4K 24

    //Undertale High School AU. Your typical High School story where you're the new girl~ //Except monsters and humans are together too. Involves time travel in later chapters. Never wrote an Reader insert before, so spare me! "You look lost there, Kiddo." A deep smooth voice caught your attention and you turned your h...

    Completed   Mature
  • Sans x Male reader
    110K 2.7K 19

    After the barriar broke, Y/n, a 18 year old boy noticed many mosters move in to houses near by, and a family of monsters and a human as your neighbors. I don't own any of the art shown here, credit goes to the one who made them. Undertale was created by Toby Fox

  • UnderMafia Sans X Reader
    118K 2.7K 19

    So since I love undertale so much and I know that not a lot of undermafia stories are out there plus this is my fifth favorite AU do why not?*chuckles*okay okay so you are working for your boss(which is frisk)You are the main hitman or collector lets just say frisk trusts you more and your really good at your job and...

    Completed   Mature
  • My Precious Item [Sans X reader]
    512 25 1

    There has been a human that was hanging around snowdin. Sans liked a certain "person" and he has been blushing whenever he sees them. They always were great in red and he loved them. Sans has been planning to confess to them but he didn't know how. Will you realized sans' feelings? Or just ignore him?

  • You're Not Half Bad For A Human. (swapfell Sans X Reader)
    265K 9.9K 55

    You are a lone girl with a normal and boring life... You worked at a convinient store just a few blocks away from your not so great House. You were a rather stoic person who didn't care much about the world. You were also a caffeine addict which wasn't so healthy, but you didn't care either way. Anyway, 3-4 years ago...

    Mature
  • You're My Pet Now {Swapfell Sans x reader}
    109K 2.3K 25

    You have fallen down a hole in a mountain by accident. You don't know what to do, and then you discover you're in the underground, a kingdom of monsters, who are quite abusive. You are trapped and you don't know what to do.....Until you meet a certain Skeleton. After that, your life changes forever.