Oh, I've read a lot of horror manga.

Pet Shop of Horror is a good manga for those who don't like to see much gore, but like to feel creeped out.

Battle Royale is... well, it is VERY scary and disturbing, let us just leave it at that...

Boogiepop Phantom is one of my favorites because it has novels, mangas, a live action film, and an anime series that all tie together. They are all pretty disturbing, but not necessarily terrifying.

Uzumaki needs to be mentioned. That's just FREAKY.

Ghost Hunt is definitely one of my favorites. I recommend this to all.