Elenco - The Mad Monster
George Zucco
Lorenzo Cameron
Anne Nagel
Lenora Cameron
Johnny Downs
Tom Gregory
Glenn Strange
Petro
Robert Strange
Professor Blaine
Gordon De Main
Professor Fitzgerald
John Elliott
Professor Hatfield
Reginald Barlow
Professor Warwick
Sarah Padden
Grandmother
Mae Busch
Susan
Ed Cassidy
Father
Henry Hall
Country Doctor
Eddie Holden
Jed Harper