Halskell

Haruo Nemoto, a dull and taciturn high school teacher, has the unique ability to become invisible when his penis has an erection. Using this ability, he manages to protect his students from various dangers without being noticed. Before him appear, one after the other, people with mysterious abilities never seen before, mysteriously beautiful women and particularly gifted girls...!?

The fate of a man who cares for his students more than anyone else begins to unfold!