These horror manga volumes were written and illustrated by Junji Ito.
The first 5 volumes were just exactly what I was looking for. In a small city, called Kurozucho, the people get affected by a strange phenomenon. A ghastly entity perhaps or just a glimpse of evil, taking the shape of a spiral is driving the people crazy.
Our main character, Kirie Goshima returned here without knowing what is due to happen. She gets involved in this strange story after seeing a man being absorbed by a spiral-shaped snail. After meeting her old friend Shuichi Saito, she gets some info about the Spiral and how this started to possess people.
Personality decay, sick subconscious, paranoia, desperation, self-destruction and death, all are effects of The Spiral.
In the first five volumes we do not find out what this Spiral is, but only that people who got obsessed with it, get consumed and they become a spiral. Shuichi’s parents will both die and became trapped into it.
Also, we do now that the phenomenon brings a sort of passion about itself. In volume 4 for example, the art of pottery is transformed into an open portal for this evil force to strike again and to make people wanting to explore it more and more.
Also, we deal with themes like friendship, love and betray, everything seen in a twisted way. I wonder what comes up next.