Possession is about the bitter dissolution of a marriage. There are… other elements, but we’ll get to them later.

First, I shall attempt to convey a sense of the viewing experience. If you’ve seen the film, I can hear you laughing.

The opening sequences assault you. Mark, played by Sam Neill, returns home to West Berlin and discovers his wife Anna, played by Isabelle Adjani, has checked out of their marriage. Neill and Adjani over-emote in performances ripped from a daytime soap opera. And yet, their scenes with their kindergarten-age son, Bob, feel restrained and true. The contrast holds your interest, as does the mystery of Mark’s job. The indirect way he talks to his employers and their responses hint at clandestine—even sinister—origins.

As the film marches on, the stakes rise. Mark moves out and spirals into an obsessive mania. When he visits some days later, Mark finds Bob alone and neglected. He moves back in and Anna disappears. In search of Anna, Mark confronts her new lover, gets bloodied, and returns home. There he discovers Anna, who won’t divulge where she’s been. Frustrated, Mark beats her.

So far, I’ve been cagey with the film’s plot points. What follows crosses into spoiler territory. Director Andrzej Żuławski’s film is a nihilistic Gordian knot of symbolism presented as psychological horror.

Anna has been disappearing to a derelict apartment where she copulates with a squid-like tentacled monster. This… thing exhibits powerful psychic abilities, possessing the mind of anyone around it.

The monster requires human flesh (or blood?) to grow, leading Anna to murder a series of interlopers, including her former lover, and a detective hired by Mark.

As the bodies pile up, the film catches up to Neill and Adjani’s performances. Now their manic behavior feels appropriate. It’s a subtle trick I didn’t catch until my second viewing. Watching Possession in a theater, the audience—full of wry snickers early on—sat riveted in silence by this point.

And I haven’t mentioned Anna’s doppelgänger or the scene where Anna—oozing blood and slime from every orifice—miscarries the tentacle monster’s offspring in a deserted subway corridor.

What is Żuławski saying? Between the talk of God and reoccurring shots of the Berlin Wall, Possession remains a mystery. One that sticks with me for days. Is it the mix of nihilism and the supernatural? Perhaps. Regardless, though I may not know why it resonates, I can’t deny that it does.