| Oh, god, Pandora Hearts thoroughly rapes the mind. With what happened to Eliott and Oz's true identity and ffff.
The ending of Sayonara Zetsubo Sensei. Masterpiece, but holy flying toaster.
When Mami got her head chomped off. After all the "yayz we're gonna be fine" and "lol hope". Oh, and finding out what Witches really were.
Finding out the truth in Mirai Nikki. And Akise's death... /sob
Once, on 4chan I came across (warning: EXTREMELY scarring)
Spoiler (mouse over to view)
a baby being raped in a page of "manga". I felt like puking all over the place. ; _; It was bleeding and... /hits head.
That bug-man from Toriko that hatches insects from his mouth. Oh, god. And Toriko's rape faces scare the crap out of me.