Angel of Darkness (1995)
Original title: 淫獣教師
Angel of Darkness is a 1995 Japanese-language horror movie directed by Mitsunori Hattori, with a running time of 1h 11m. It stars Seiko Seno, Ayu Shinohara and Mariko Motoki.
At a high school in Tokyo, several of the female students have been moon-lighting as prostitutes. A teacher catches onto this fact and goes about putting an end to it. Things go awry when he discovers he turns into a sex demon with tentacles whenever he gets aroused or angry.