The plot is pretty well laid out here already, so I'll just say that THE DEVIL BAT is one of the best Bela Lugosi poverty-row horrors. It was made for Producers Releasing Corp (PRC) in 1940. I think it's as good, perhaps better than any of the titles in his Monogram resume. In general, PRC delivered the goods with their horror pictures, and if what you're looking for is peak Bela madness- wild eyed and possessed, than DEVIL BAT will definitely satisfy. A sequel, DEVIL BAT'S DAUGHTER, came in 1946, and GEORGE ZUCCO starred in a remake, THE FLYING SERPENT, in 1946.
Review of The Devil Bat
