The Harry Potter movies notoriously cut some key moments from the books, including one in The Order of the Phoenix that explains what happened to Gilderoy Lockhart. First introduced in The Chamber of Secrets, Lockhart was an arrogant wizard who was famous for his various feats of bravery. He became the Defense Against the Dark Arts professor at Hogwarts, only for everyone to notice that he wasn't quite as brave or honest as he seemed.