Psychological Doubling
Pairing the main character with a second character who mirrors them. The double shows what the hero wants, fears or secretly is.
The Tenant
Trelkovsky starts to become Simone Choule, the woman who lived in the flat before him. He orders her usual drink at the cafe, smokes her brand and puts on a wig and her dress. By the end he repeats her fall, so the double is what he fears he is turning into.
Lost Highway
Fred's wife Renee has a double in Alice, the mistress of the gangster Mr. Eddy, and Fred has a double in Pete, a young mechanic. Each double acts out what the original can't face. Pete gets the life of confident desire that Fred has lost.

