One of the many Paul Naschy films as the werewolf "Waldemar Daninsky". Per Wikipedia: "1971 Spanish horror film starring Paul Naschy, the fifth in a series about the werewolf Waldemar Daninsky. This film... is generally regarded to have kickstarted the Spanish horror film boom of the 1970s, due to its awesome box office success upon its release." That said, the ambling plot and silly, pre-Underworld vampire/werewolf rivalry should make it worthy of riffing! See https://en.m.wikipedia.org/wiki/La_Noche_de_Walpurgis