10 Most Confusing Horror Movies You'll Ever Watch

Inspired by the research of psychonaut John C. Lilly, Altered States tells the story of scientist Eddie Jessup (William Hurt), who believes genetic memories can be unlocked with drugs and sensory deprivation.

Jessup has a breakthrough when he discovers a psychedelic which doesn't just alter his mind, but his genetic composition. Upon sampling this drug, Jessup goes full Jekyll and Hyde, devolving into a savage caveman. Eager to see how far he can regress, Jessup continues to use himself as a guinea pig, deteriorating to a primordial mass, then a single-cell state, and finally, a non-physical but conscious entity.

Much like Jessup, director Ken Russell pushes the boundaries of reality and explores the depth of human consciousness as far as he can. Delving into the limits of scientific knowledge, the nature of existence, the fragility of the human mind, and the consequences of tampering with the unknown, Altered States gives viewers a banquet for thought.

And because the obscure imagery is rarely explained, all references to mushroom people, the Shroud of Turin, and the seven-eyed ram-man feels not just ambiguous, but unknowable.