Movies about massive blood loss and things that go bump in the night are such a staple to the “scary movie” category that I always feel like an idiot when I say the scariest one I’ve ever seen is an Australian flick about girls who go picnicking.

But Peter Weir’s 1975 film Picnic at Hanging Rock tops The Exorcist or any other Halloween classic in my book. The legendary director went on to make Dead Poets Society and The Truman Show, but he never made a more fascinating or effective movie than one of the first he ever made. It’s a far cry from levitating bodies and molested crucifixes, but it’s a great alternative to going through the Nightmare on Elm Street series for the eighth time.

The movie takes place in Australia in 1900 and begins at an all-girls boarding school on St. Valentine’s Day. The school arranges for 19 of the teenaged girls at the school to travel to a geological oddity called Hanging Rock: a massive, mountainous pile of stone that looms ominously on the horizon like the secluded castles in mad scientist movies.

Many of the girls and teachers sit idly around the base of the rock for the afternoon, eating and relaxing, but a small group takes it upon itself to explore. This is where the movie goes from unsettling to terrifying. The small group of girls and one teacher wander deeper and deeper into the rocks, and then they just disappear. No dramatic vanishing, no sudden violence — they just don’t come back. Those resting at the base of the rock notice their watches all stopped at about noon, right around the time they disappeared.

From there, Weir fashions one of the greatest mind games in the history of the movies. An epigraph before the film begins says the girls were never found, so we know Rock will end with the mystery unsolved. And the subtle eroticism created earlier in the film — snakes crawling on the rocks, the girls removing their stockings in slow-motion, two teenage boys seeing the girls before they vanished — continues to develop, implying that what happened to the girls could be far worse than getting stuck inside a cave.

But what is important about Picnic at Hanging Rock is that we never know, and that is what makes it, even on repeat viewings, infinitely more disturbing than a knife-wielding psycho who is unmasked at the end while the D-cup heroine escapes alive.

Rock is a movie that proves what is “scary” has become far too pigeonholed when it comes to the movies. Watching it alone with the lights off makes Child’s Play feel like, well, child’s play.