As Seen In: American History X (1998)
There are only two ways a person can sit through the above scene from American History X without either shutting their eyes or covering them with their hands: They're either blind or their eye-lids are propped open Clockwork Orange style. Otherwise, they're one desensitized son of a bitch.
Edward Norton is a force of nature in the film, playing a skinhead who's the worst kind of influence on his younger brother, Danny (Edward Furlong). Lucky little bros get to watch their older male siblings work hard, kick it to girls, etc. But not Danny. His role model forces a black kid to get on his stomach and bite down on the curb.
We'll let you witness the rest for yourself, but just know that it involves a human skull getting cracked in half like a cashew. Good luck chewing for the rest of the day.