Mad Monster Party? (1967)

As Dr. Frankenstein prepares to step away from his life of creating monsters, he invites a diverse assembly of legendary creatures to a spooky gathering to choose his successor. Among the attendees are Dracula, The Werewolf, The Creature, and Dr. Jekyll & Mr. Hyde, among others. However, the stakes go beyond just the title; the renowned doctor has also unearthed a dangerous secret of complete annihilation that must be kept out of the wrong hands!