John Brahm was a German film and television director. His films include The Undying Monster (1942), The Lodger (1944), Hangover Square (1945), The Locket (1946), The Brasher Doubloon (1947), and the 3D horror film, The Mad Magician (1954).

The Undying Monster, also known as The Hammond Mystery, is a 1942 American mystery horror film directed by John Brahm and written by Lillie Hayward and Michel Jacoby, based on Jessie Douglas Kerruish's 1922 novel of the same name. The film stars James Ellison, Heather Angel and John Howard, and focuses on a series of mysterious deaths within the wealthy Hammond family.