It's probably about Rarity :)
And Rarity is my favorite character!!

Lil Miss Rarity is a creepypaste version of Rarity, where she is a psychopathic serial killer, who cuts ponies and whatnot. Like Pinkamena... horrible, sick shit, basically.

Lil Miss Rarity was a tumblr blog that ran a while back. It starred Rarity, who after Pinkie went crazy and started killing ponies became infatuated with her and developed a liking for BDSM, meaning she derives sexual pleasure from bondage, inflicting harm, restraint, restraint and inflicting harm on other ponies.
She started with accidentally killing her cat, to which she realized she loved it. She began to cut herself up, cutting a large heart in her chest and fantasizing about Pinkamenia killing her in a brutal fashion. Somewhere along the track she decided to inflict pain on Sweetie-belle but stopped after Twilight found her. She knocked Twilight out so she forgot and Sweetie was blindfolded so no-pony knew she did it.
It was then found out Sweetiebelle also likes BDSM, even trying it with her friends.
Then Rarity, after being haunted by the ghost of her cat (She made her into a plush doll using her fur), Pinkamenia captured her. Even to her best attempts, Pinkie could not kill Rarity. Even when she made her into a suit she would just regenerate like nothing happened, much to Rarity's sick pleasure. She then wondered if it was 'The power of friendship' and seemed happy that even after she had become a monster she still brung a smile to Rarity's face.
After a while Rarity wakes up and she is back in the normal universe. Everyone is alive and Pinkie is still completely sane and the happy pony she usually is.
The blog ended with Rarity stating this;
"But do I want this? This world, it's so peaceful and happy like the old days... Nah! Haha, of course not! I have a lot of work to do!" Then her grinning like a maniac.

In short:
ITS MESSEDDDD UPPP YOOOOOOOOOOOOOOOOOO