1. Altered States
Not content with demonstrating the effects of the hallucinogenic caapi root, this 1980 sci-fi horror also shows us just how the mind manages to keep itself together after a stint in a sensory deprivation chamber (answer: it doesn't) . Our guinea pig is Dr Edward Jessup (William Hurt), a professor of abnormal psychology who is actively searching for ''other states of consciousness''. Fortunately for him, there's a messed-up montage of religious imagery (complete with Bibles, fish, shrouds, crucifixion, fire, animal sacrifice, devil worship and eight-eyed goats) just waiting to worm its way into his brain. And yours, too. For the whole film is one giant bubbling beaker of crazy. For a tiny taste of the film's true flavour, watch the below clip. It's as strange, sinister and gloriously unsubtle as one of those conspiracy theory videos you find in every corner of YouTube. Only with added WTF.