Hiss and Yell (1946)

Vera thinks she's witnessed a man decapitating his wife. Actually, she's only seen magician Bluebeard the Great rehearsing his act. Still convinced that the magician is a killer, Vera goes through all sorts of comic agony when she is forced to share the same train compartment with Bluebeard (who doesn't help matters when he offers her a sandwich consisting of "scrambled brains and tongue").

Unfortunately the movie Hiss and Yell is not yet available on HBO Max.