The Invisible Maniac (1990) Asylum escapee turned teacher takes invisibility formula to terrorize taunters and perv on teenage girls. It's enough to make you reconsider the idea of tenure. TIL: To paraphrase Dwight L. Moody, character is who you are when no one can see you.
Your daily dose of culture courtesy of Dracula Vs. Frankenstein (1971) - "Avoid foolish and ignorant debates, for you know that they breed quarrels." - 2 Tim. 2:22