Naked Lunch

In 1953, exterminator William Lee finds that his wife Joan is stealing his supply of insecticide to use as a recreational drug. Lee is arrested by the police, and he begins hallucinating due to being exposed to the insecticide. Lee comes to believe that he is a secret agent, and his boss, a giant talking beetle, assigns him the mission of killing Joan, who is allegedly an agent of an organization called Interzone Incorporated. Lee dismisses the beetle's instructions and kills it. Lee returns home to find Joan having sex with Hank, one of his writer friends. Shortly afterwards, he accidentally kills her while attempting to shoot a drinking glass off her head to emulate William Tell.