Black Christmas Movie Poster

Billy Edward Lenz (Robert Mann), a boy born with a rare liver medical condition that makes his skin yellow, is constantly abused and hated by his mother, Mrs. Lenz (Karin Konoval), due to her hate towards her husband. Setting her eyes on another man, she has him kill her husband, and they bury his body in the underground crawlspace under the house. When Billy is seen witnessing this, she locks him in the attic.
After few more years, when Mrs. Lenz tries to conceive a new baby with her new man, she realizes he is impotent, and goes up to the attic and sexually assaults Billy. Soon a daughter named Agnes (Dean Friss) is born and treated like a princess.
When Agnes is eight and Christmas comes around, Billy escapes and disfigures Agnes by gouging out her eye and then calls his mother taunting her saying, "she's my family now." Mrs. Lenz, horrified, runs from the kitchen screaming for her son and with her lover find Agnes with a bag over head screaming in pain and terror. Mrs. Lenz' lover charges at Billy, but is stabbed through the eye with an umbrella. Horrified, Mrs. Lenz attempts to run away, but Billy wraps the Christmas lights around her neck and drags her into the kitchen, where he beats her to death with a rolling pin. He grabs a cookie cutter and proceeds to make cookies out of his mother's flesh. He is caught by the police, who arrive at the house to see him eating the cookies and dipping them in milk which has him sent to a mental asylum.