Summer school can be deadly... especially when the nerdy new physics professor is a voyeur with a vengeance who's making himself temporarily invisible... and making the student body permanently disappear! Not that his classroom full of over-sexed underachievers don't deserve a dose of discipline. Ever since his arrival, they've been neglecting their physics and taunting him with their physiques... unaware that he's actually a mad scientist who was locked away for murdering several colleagues, only to escape in order to continue work on a serum that makes him invisible. Now, however, their teasing has pushed him over the edge and now he's getting even.
Taunts turn to terror as clothes and class attendance begin to drop off, with each student fighting a creatively grisly, but ultimately losing battle with an unseeable assailant. Finally, the sole survivor injects himself with the serum to teach the professor a lesson. Their invisible duel to the death is a shocker you've just got to not see to believe!

Us release date: July 13, 1990