I Know What You Did Last Summer (1997)

Plot hole: Barry gets killed violently at the pageant. So obviously there should be blood everywhere. When the police go up to the crime scene, they find nothing. There's no way the killer had time to clean up anything, let alone drag away Barry's body without someone seeing him. And blood starts dripping after the police leave the scene.

Officer David Caporizo: Oh, and did this killer use his hook to cut all your hair off?
Helen: No, he used scissors, asshole.

Trivia: Max (Johnny Galecki) was killed to beef up the body count. The scene was filmed after principal photography.