Psycho (1960)

Alfred Hitchcock's decision to kill his apparent lead actress 47 minutes into the film shattered every convention audiences held about narrative safety and created the template for every slasher film that followed. Made for under $1 million and grossed over $50 million — a return of roughly 6,000% — it introduced the subjective killer's-eye-view camera that became the grammar of the entire genre. Norman Bates, the Bates Motel, and the shower scene remain among the most referenced images in cinema history.