Spider Baby

Spider Baby is a 1968 black comedy horror film, written and directed by Jack Hill that was shot in 1964. It stars Lon Chaney, Jr. as Bruno, the chauffeur and caretaker of three orphaned siblings who suffer from Merrye Syndrome, which causes them to mentally, socially, and physically regress backwards down the evolutionary ladder starting in early puberty. Carol Ohmart, Quinn Redeker, Beverly Washburn, Jill Banner, Sid Haig, Mary Mitchel, Karl Schanzer and Mantan Moreland also star.

The siblings, Ralph Haig, Virginia Banner and Elizabeth Washburn, are inbred, demented and dangerous. These overgrown children exhibit playful innocence mixed with brutality and feral madness. Virginia is known as Spider Baby because of her obsession with spiders. She stalks and eats bugs, moving with a strange and spiderlike grace. She also enjoys trapping unsuspecting victims in her rope web, stinging them to death using two butcher knives. After murdering an innocent delivery man Moreland, Virginia cuts off one of his ears, which she keeps in a match box.Ralph is a sexually advanced but mentally deficient simpleton who moves through the house via the dumbwaiter. Unable to speak, Ralph communicates with only grunts and leers. He becomes sexually aroused with the arrival of the two visiting women. ........

Source: Wikipedia