"If Mirrors Could Speak" is a super creepy educational film from 1976 in which misbehaving kids are presented in clown make-up.
In hopes of keeping kids' attention, social engineering films would often use supernatural elements to make their points. In this film, we see a magic talking mirror that reflects bratty kids as clowns. Most of the misbehaving kids understand how their behavior is disruptive and make amends. Surprisingly, one kid doesnt care if he is a "clown" and continues being a jerk probably for the rest of his life.This film is included in archive.org's stupendous "A/V Geeks Film Archive"