Monstrosity is a 1964 film directed by Joseph V. Mascelli. It is perhaps better known under its alternate title, The Atomic Brain.
The movie tells the story of an elderly woman who uses her vast fortune to convince an eccentric yet brilliant scientist to provide her with a new, youthful body. This is done by hiring three immigrant young women, with the promise of helping them become film stars. The old woman then chooses which of the girls she finds most beautiful, and sets about replacing the young woman’s brain with her own.