Theatre of Blood (1973)

Plot hole: Edward Lionheart severs the head of theater critic Horace Sprout while Sprout and his wife are asleep. (Lionheart gave them both a knockout injection). Sprout's wife (and his maid)discover the severed head in the morning, and both scream and faint. But in the next scene, critic Perry Devlin retrieves his morning newspaper and then reaches for his bottle of milk, only to find Sprout's head perched on the milk bottle. How did the head get from Sprout's house to Devlin's place?

Inspector Boot: Who hates you enough to kill two of your circle?
Peregrine Devlin: Critics are likely to make enemies, inspector. You can call it an occupational hazard.

Trivia: One of the movie critics that Edward Lionhart kills in the movie is Miss Chloe Moon, played by Coral Browne. In real life, Vincent Price and Coral Browne fell madly in love while making this movie, and they married shortly afterward, and remained married until her death in 1991.