6. Harvey Stephens Was Instructed To Attack Director Richard Donner (The Omen)
1976's The Omen is - to crudely sum up an interesting plot - all about a creepy kid called Damien Thorn, who is actually the evil Antichrist. If audiences didn't find Damien spooky, then the movie just wouldn't work. It would probably be laughable.
Fortunately though, Damien was really creepy, and that's largely because director Richard Donner was extremely thorough in his search for a child star, a process that included a rather unusual test for all the prospective candidates.
While looking for the right young actor, Donner asked the auditionees to perform the scene where Damien attacks Katherine at a wedding. While this might not sound too strange at first, it most definitely does become strange when you learn that - in order to make the audition scene feel as close to the real thing as possible - Donner decided to let the kids physically attack him.
Harvey Stephens (who ended up playing Damien) was reportedly told by Donner to "come at him", so that Donner could see how angry and scary the kid could get.
In response, Stephens charged and started clawing at Donner's face, and even kicked him in the groin. He immediately won the part. And the rest is history.