Undertail Stories

376 Stories

Lust's Little S!ut [FEMALE READER] by GalaxyTheFur
#1
Lust's Little S!ut [FEMALE READER]by Edgy_Bean
⚠️WARNING: THERE WILL BE CUSSING AND SEXUAL ACTIVITY⚠️
It's Not Possible ( Nightmare x Killer ) by jesus_davito13
#2
It's Not Possible ( Nightmare x Ki...by Abomination.
It's almost the end of highschool for Killer, an 19 year old student at a human and monster school on the surface. Killer isn't ready to leave the highschool yet as he's...
Completed
Falling in pun with you (Completed fontcest Story)  by Intellectualpan
#4
Falling in pun with you (Completed...by Jessica
A skeleton named Sans falls in love with the only thing that makes him happy, that made him feel complete... his brother Papyrus. But when sans suspects papyrus of falli...
Of a Better World by toast_and_bunz
#5
Of a Better Worldby toast_and_bunz
It's been a while since Horror's world could be considered even remotely kind. But a newcomer drops in, and reminds him that there's still sweetness to be found in life...
Classic x fell (lemon) by JackPutman
#6
Classic x fell (lemon)by JackPutman
Plz give me suggestions of what to do next and if I don't upload for a while it's because I have important things like school homework and I'm probably thinking about wh...
Tangled Strings (An Errink Fanfic) by Artist_Bean_Baby
#7
Tangled Strings (An Errink Fanfic)by Artist_Bean_Baby
The art for the title cover is by Pencil_loves_mm on Twitter! Creation and Destruction able to find a balance and keep peace? ...maybe.
The Blue Hearted Hero (bnha x undertail fanfic) by crimson518
#8
The Blue Hearted Hero (bnha x unde...by Daniel Roberts
" why dont you just take a swan dive off a building and hope that in your next life you get a quirk " was the greatest advice given to the quirkless boy izuku...
Adult Frisk +18 by CharaTheLustfulDemon
#9
Adult Frisk +18by Chara The Lustful Demon
What Should I Describe Here? I Guess The Title Already Says Everything so Far
ONLY ONE {Yandere!Sans x Reader} by DancingInThePetals
#10
ONLY ONE {Yandere!Sans x Reader}by *•Pastel•*
Hello! Here is a fanfic that I will write for you people who wanted this but couldn't find any.
It's okay sans x frisk by solarflamer
#11
It's okay sans x friskby solarflamer
Frisk got the monsters up above, yet she can't help the bad gilt that comes with her new dreams she falls into depression. And starts to cut. Then when someone finds out...
Bad Sans Poly Stuffz by Sapperz
#12
Bad Sans Poly Stuffzby SappySapperz
Ah here we go first time writing h a h. Anyways. Lil quick warning there will be -Smut -Fluff -Angst -And some kinks (For example size difference) If you do not enjoy a...
Maid For The Day by LazyBones23
#13
Maid For The Dayby LazyBones23
Chara is going to learn that pushing Sans too far doesn't come with out consequences... very suggestive consequences~~
Error Uke oneshots[REQUESTS OPEN] by CharlieEatsWaffle
#14
Error Uke oneshots[REQUESTS OPEN]by Waffle-Man, the gayest hero!
basicaly a big book of my favorite sans in my favorite role;Error as a bottom.
A collection of bad fanfics by powermittens
#15
A collection of bad fanficsby End my suffering
A contest between friends I'm sorry you had to witness this horrible story.
Completed
I dunno some Undertale au lemon shit by PopRocksbnha
#16
I dunno some Undertale au lemon sh...by PopRocksbnha
This is just some stuff I came up with at night time. By the way all of the submissive are females because I find it harder to write them as males. Don't know why.
omotale one-shots by WingedWhiteTIGER
#17
omotale one-shotsby Angel
this is full of omotale stories I write please excuse my Shity spelling and grammar this is NSFW I do take requests some fontcest
Sans in Heat X Reader  by Sinnnnnnnnnnnnn
#18
Sans in Heat X Reader by Sinnnnnnnnnnnnn
This is my first fanfic so don't judge too hard please... anyways, hope you like it you sinner ;) (18+!!!! Well, if you're younger I guess I can't judge you. I'm not...
Sanscest One-Shots by Apple_Bxtches
#19
Sanscest One-Shotsby Wabaa
It is quite simple!! Just a bunch of stories that are hopefully enjoyable! The updates will be slow and sometimes I upload more than once a day! Also the cover is MY art...