The Mark of the Wolfman (Spanish: La Marca del Hombre Lobo), is a 1968 Spanish horror film, the first in a long series of films about the werewolf Count Waldemar Daninsky, played by Paul Naschy. The film was also known as Hell's Creatures, The Nights of Satan, The Vampires of Dr. Dracula and Frankenstein's Bloody Terror (the latter despite the fact that the film has nothing to do with either Frankenstein or his "bloody terror"). Naschy originally suggested actress Barbara Steele for the part of the vampire countess Wandesa, but Aurora De Alba wound up getting the part.

The film was in production from February to March 1968. It was first released theatrically in Spain (on July 29, 1968), in West Germany (on February 7, 1969), in the U.K. in February 1970 (on a double bill with The Night God Screamed (1970)), and finally in the U.S. in a slightly shortened version as Frankenstein's Bloody Terror in 1971. It was released to late-night television (edited) in the U.S. in 1974. The film was shot in Hi-Fi 70mm 3-D, but was only shown that way at a brief engagement in Munich, Germany, and in several select theaters in Hollywood (reviews mentioned the 3D effects looked somewhat shoddy).

The film is available on DVD from Shriek Show as Frankenstein's Bloody Terror, as well as on a German Blu-Ray (Region 2) under the title Die Vampire des Dr. Dracula.

Naschy claimed he followed up this film with a 1968 film Las Noches del Hombre Lobo (which is today a lost film, if indeed it was ever completed at all, since no one has ever seen it) and his 1969 film Los Monstruos del Terror.