I had a request for this link, which I got from Incabulos.

Uzumaki

It's a creepy series about a small town in Japan that is plagued by spirals. Much better than I make it sound.

Ito is pretty awesome in regards to Horrormangas.

This is awesome, I can't get enough!!! *eyes roll around separately* Trying to limit myself to just one chapter a day to savour all the twisted goodness but I'm afraid that will be impossible

Also try:
Gyo
Enigma at Amigara Fault

There's also a series called 'Fuan no Tane' that contains lots of weird short stories.
Some of them are just odd, some of them are deeply, deeply unsettling.