Steven Seagal
It's no secret that Steven Seagal doesn't have the best reputation on set. However, this one goes way far beyond few wayward comments. Seagal reportedly sent a stuntman to the hospital for surgery due to his recklessness. Instead of throwing the stuntman to his prepared mark, the actor "drove the guy's top teeth through a portion that wasn't prepared to break. This broke the stuntman's maxilla (upper jaw) and knocked out most of his teeth." Since then, the stuntman has gone through multiple surgeries to repair his jaw.