The Enigma of Amigara Fault(2000)

Amigara Dansou no Kai

A short horror manga story by Junji Ito, printed as a bonus one-shot alongside his fish-zombie-apocalypse manga Gyo. A boy named Oowaki, and a girl, Yoshida, meet on Amigara Mountain, where an unsettling discovery has been made. Human shaped holes are scattered across the mountain, and it soon becomes clear that the holes are "calling" to the people they are shaped like. So what happens when they enter the hole? Well, you can be sure that massive amounts of claustrophobia and Nightmare Fuel are involved.