The Mafu Cage (also released as My Sister, My Love, Deviation and Don't Ring the Doorbell) is a 1978 American psychological horror film directed by Karen Arthur, and starring Carol Kane and Lee Grant. Its plot follows two sisters, both the daughters of a late anthropologist, residing in a dilapidated Los Angeles mansion: one, is an astronomer, and the other, is a dysfunctional eccentric who keeps and tortures a variety of monkeys and other primates.

Arthur worked with screenwriter Don Chastain to loosely adapt Eric Westphal's play Toi et Tes Nuages, which she had seen in Paris in 1975. The finished product premiered at Cannes in 1978.