15 Most Disturbing Horror Movies Ever

The horrors of World War II’s human experimentation have been seen on film in everything from 1988’s Men Behind the Sun to 1994’s cat-starring murder mystery Felidae (yes, really), but this horror from Spanish director Agusti Villaronga is the most chilling cinematic exploration of the topic—and one of the most unsettling movies ever made to boot.

Our nominal protagonist is a murderous child molester who has been confined to an iron lung after a suicide attempt, setting the scene for the cheerful story to follow.

A former Nazi, the aging killer is tended to by a new nurse who—surprise!—turns out to be a survivor of his twisted wartime tortures, prompting a horrific string of torture and murders which play out in agonizingly slow, deliberate sequences almost impossible to watch.

The film skirts with attempts at character drama, but its explicit and deeply upsetting content ensures that nothing like redemption or hope can escape the celluloid, and the horrifying story plays out as a scarring horror story which no viewer could forget—if they can make it to the end.