The Pyx, also known as The Hooker Cult Murders and La Lunule, is a 1973 Canadian horror film directed by Harvey Hart and starring Karen Black, Christopher Plummer, Donald Pilon, and Jean-Louis Roux. Based on John Buell's 1959 novel of the same name, it follows a Montreal police detective unraveling the mystery behind the death of a heroin-addicted prostitute who died under bizarre circumstances after falling from a building. Its title refers to the pyx, a small container used by the Roman Catholic Church to hold sacramental bread.