Psyren! I know, I know, I said the ending sucks and I told you all not to read this series whatever you do because you'll get heartbroken for life... But I completely accidentally started re-reading it, and was overwhelmed by how awesome this manga is! So basically, I do recommend it for everyone to read. Just, idk, pretend that ending was different or something.
Motivational pics:
Shingeki no Kyojin - and now we're off to creepy land D: Or rather, a land even creepier than Psyren. In this manga most of the humanity has been devoured by nearly invincible giants named Titans. The miserable remains of the humankind are hiding behind 50m high walls and hoping those will protect them from Titans. Too bad it doesn't quite work like that... This is where our hero Eren and his adoptive sister Mikasa come in. Although it is not known whether they will be able to save the world or die trying (more likely, since just about every character dies a horrible gruesome death here).
Motivational pics (or demotivational, as the case may be):
The atmosphere is really creepy in this one, and the levels of blood and gore are higher than in Gantz!
And the third rec is something more light-hearted, although not for the weak of stomach XD
Ito Junji's Cat Diary - a manga by a well-known horror manga author, in which he describes his everyday life with cats. And since he is a horror manga author, the art style is very much like in a horror manga, so no cute kitties or anything here XD
Motivational pics:
Also, I'm leaving for my interpreting job tomorrow morning, so wish me luck, or better yet, wish me not to forget the little German that I know...