Son of Dracula (1973)

Due to be crowned King of the Netherworld by his mentor Merlin the Magician (Ringo Starr) at a monster's convention, Count Downe (Harry Nilsson), the son of Count Dracula, falls in love with the beautiful, but human, Amber (Suzanna Leigh) and finds himself in conflict with Baron Frankenstein (Freddie Jones), who is vying for the same honorary title.