Los Monstruos del Terror (The Monsters of Terror), also known as Dracula vs. Frankenstein and Assignment Terror, is a 1969 Spanish/German/Italian horror film that is the third in a series featuring the werewolf, Waldemar Daninsky, played by Paul Naschy.
Aliens from a dying world plot to conquer earth by praying on man's superstitions. Bringing two dead scientists (Michael Rennie and Karin Dor) back to life, they use their knowledge to re-animate various earth monsters, including the werewolf Waldemar Daninsky, Frankenstein's monster (both played by Jacinto Molina), the mummy Tao-Tet, and the vampire Count de Meirhoff.
I remember watching this film late at night during Nightmare Theatre on Kiro TV 7 in Seattle Wa when I was a kid. Always loved Italian horror films.
ASSIGNMENT TERROR TULIO DE MICHELLY (1969) 81 MIN ITALY