Known for being the most horrifying, disturbing My Little Pony fanfiction ever. Was first posted on 4Chan, then posted on a website called Equestria Daily.
In this fanfiction, Rainbowdash (A character from the popular show My Little Pony: Friendship is magic) goes to see Pinkie Pie (Another character) of whom has told her they were going to do something fun together. Pinkie Pie then proceeds to explain they're going to make Cupcakes.
Upon finding this out, Rainbowdash is force-fed a cupcake that puts her into a deep sleep. When she wakes up, she's tied with her legs spread open. Pinkie Pie then proceeds to cut her friend open in intimate detail, and after she dies bakes her into cupcakes of which she feeds to her friends.
Bronie: Dude have you read the Cupcakes Fanfiction?
Bronie 2: Yeah, and I still am too scared to eat a cupcake!
The most fucked-up, mentally scarring fanfiction you will ever read. Also happens to be about My Little Pony. The plot:
Rainbow Dash goes to see her friend Pinkie Pie. Pinkie makes her eat a cupcake, which makes Rainbow fall asleep. When she wakes up, she's strapped down in Pinkie's basement (which is filled with other pony's body parts, made to look like they're at a party) Pinkie then proceeds to skin Rainbow's cutie mark off, cut off her wings, EAT PART OF RAINBOW'S LEG- etc. Rainbow eventually dies and Pinkie puts her in a cupcake.
I just read the Cupcakes Fanfiction. I will never eat a cupcake again without throwing up.