白濁クダサイ

After class ends the protagonist finds a classmate acting strange and unresponsive and leaving a notebook on the desk.

Taken by curiosity the MC takes it home. It contains a manga of his classmates being assaulted.
The next day the teacher says that the classmate from the previous day is gone missing.

The mc soon discover that the contents of the notebook has changed and after that he seems to experience them himself. It displays his delusions and desires.