

Karloff + Lugosi in a 70-minute brain-swap fever dream? The 1940s said 'let's get weird.'
University professor George Kingsley is struck by gangsters while crossing the street, leaving him with brain damage and one of the gangsters, Cannon, paralyzed. Kingsley's friend Dr. Sovac attends to both men, and when Cannon offers him a reward for aiding his recovery, Kovac transplants part of Cannon's brain into the dying Kingsley's skull, creating a dual personality.
Acting
Stanley Ridges out-acts both horror legends somehow.
Direction
Arthur Lubin keeps this ridiculous premise actually coherent.
Production
Universal B-movie magic on a shoestring and a prayer.

Director
Arthur Lubin
Trivia, insights & behind the scenes
Karloff and Lugosi share barely any screen time—Universal famously billed them together while minimizing actual interaction to save on scheduling conflicts.
This was one of the last horror films before the genre got neutered by the Production Code; the brain transplant premise barely squeaked through censors who found it 'repellent but not immoral.'