Brian De Palma‘s Carrie is remembered for a bucket of pig’s blood, but its lasting power is quieter and crueler than that. De Palma took Stephen King‘s first novel and made the genre’s rarest thing: a horror film that works as a tragedy. The monster here is not telekinesis. It is a school, a mother and a town that decide a strange girl is fair game — and the terror comes from watching how completely they are right until, for one night, they are catastrophically wrong.

Sissy Spacek plays Carrie White as a raw nerve, a teenager kept ignorant of her own body by a mother who has confused shame for salvation. The film opens on a locker room and a first period Carrie mistakes for dying, and the girls who should help her instead pelt her with tampons while chanting. That scene sets the machine in motion. Everything that follows — the prom invitation engineered half in guilt and half in cruelty, the pig’s blood rigged above the stage — is just the town collecting on a debt it has been building Carrie’s whole life.

Opposite Spacek, Piper Laurie gives one of the great horror performances as Margaret White, a religious fanatic who treats her daughter’s puberty as proof of sin. Laurie plays her not as a cartoon but as a woman genuinely convinced she is loving her child by breaking her, and the film’s most frightening rooms are the ones with no supernatural event in them at all — just a mother, a prayer closet and a kitchen knife. Spacek and Laurie were both nominated for Academy Awards, a near-unheard-of gesture toward a genre picture at the time, and neither honor was courtesy.

De Palma directs it as bravura cinema, unafraid to show off. He shoots the opening in a dreamy, voyeuristic slow motion straight out of Hitchcock — the high school is even named Bates — and scores the dread with Pino Donaggio’s shrieking strings, which quote Psycho without apology. Then, at the prom, he splits the screen in two: Carrie’s face on one side, the carnage her mind unleashes on the other, so the audience watches her become executioner and victim simultaneously. It remains one of the most audacious set pieces in American horror, technique deployed not for spectacle but to keep us trapped inside her point of view.

The ensemble around the two leads reads now like a casting time capsule. John Travolta, months from Saturday Night Fever, plays the boyfriend-thug; Nancy Allen is the queen bee who lights the fuse; Amy Irving and William Katt are the couple whose decent instinct only hastens the disaster; Betty Buckley is the gym teacher who tries and fails to stand between Carrie and the room. De Palma stages their high-school world as pure archetype, and that broadness is the one place the film shows its age — but it also makes the cruelty legible in an instant, which is exactly what the tragedy needs.

What Carrie ultimately changed was the shape of fear itself. Its final graveyard shot — a hand bursting from the earth to grab the last survivor, revealed as a nightmare — codified the “one more scare” ending that every horror film since has either used or been measured against. King’s debut novel launched the most durable career in American popular fiction, and this adaptation proved his material could carry weight far beyond the paperback rack, seeding a Broadway musical, two remakes and a franchise afterlife that never quite recaptures the original’s ache.

That ache is the point. Five decades on, the pig’s blood is the poster and the punchline, but the film underneath is a study of how ordinary people manufacture a victim and then are shocked when the victim has power. De Palma’s craft is dazzling; the reason it endures is that he pointed all of it at empathy. Carrie is essential horror precisely because it makes you grieve the girl you were told to fear.