Villian(s)  Satanism, demonic possession

Actor(s):  Alan Alda, Jacqueline Bisset, Barbara Parkins, Bradford Dillman

Brief Description  The Mephisto Waltz (1971) is a stylish occult horror thriller directed by Paul Wendkos, adapting a novel by Fred Mustard Stewart. Capitalizing on the late-60s and early-70s Satanic cinema craze ignited by Rosemary's Baby, the movie follows a terminally ill, elitist piano virtuoso who uses dark magic to transfer his soul into the body of a younger, frustrated music journalist.

Plot:
Myles Clarkson (Alan Alda) is a failed concert pianist turned music journalist. He manages to secure an interview with the legendary, wealthy, and arrogant virtuoso Duncan Ely (Curd Jürgens). Duncan is initially dismissive of Myles, but his attitude shifts dramatically when he notices Myles's hands. Duncan realizes Myles has the perfect physical build and "hands" to be a world-class pianist. Unknown to Myles or his wife Paula (Jacqueline Bisset), Duncan is the leader of a wealthy Satanic cult. Dying of leukemia, Duncan performs a complex occult ritual involving a mysterious "blue goo" shortly before his death. This ritual successfully transfers Duncan's consciousness and musical soul into Myles's young body.

After Duncan dies, Myles's personality changes drastically. He suddenly becomes a masterful piano virtuoso overnight, drops his journalistic career, and inherits Duncan's massive estate and opulent lifestyle. He also grows cold toward Paula and begins an incestuous affair with Roxanne (Barbara Parkins), who is secretly Duncan's daughter and fellow cult member. Paula becomes intensely suspicious of her husband's sudden musical genius and altered personality. Her dread turns to horror when their young daughter dies under mysterious, occult-related circumstances, prompting Paula to investigate the cult's activities.

Realizing that the man in her husband's body is actually Duncan Ely, Paula knows she cannot defeat the cult or get the original Myles back. Instead of fleeing, she uses the cult’s own dark magic against them. Paula initiates a Satanic ritual of her own. She transfers her own consciousness into the body of Duncan’s daughter, Roxanne, and murders Roxanne's original soul. The film ends on a deeply macabre twist: Paula (now inside Roxanne's body) embraces Duncan (inside Myles's body). To the outside world, it looks like Myles is carrying out an affair with Roxanne, but in reality, the original husband and wife are reunited, though trapped forever in entirely different bodies and bound to a sinister lifestyle.