Theater Bizarre: Fury of the Wolfman

The Fury of the Wolfman (Spanish: La Furia del Hombre Lobo), aka Wolfman Never Sleeps, is a 1970 Spanish horror film that is the fourth in a long series about the werewolf Count Waldemar Daninsky, played by Paul Naschy. Naschy wrote the screenplay as well. The film was shot in early 1970. It was not theatrically released in Spain until 1975 due to problems involved in finding a distributor, although it was distributed in edited form on U.S. TV in 1974.
A Swedish edit called Wolfman Never Sleeps has a longer running time and contains several extra nude sex scenes that were edited out of the regular version. Romana Gonzalez handled the werewolf makeup effects. Naschy had a very hard time working with the director Jose Maria Zabalza, who he said was usually drunk on the set and tampered enormously with Naschy's screenplay. There are claims that Zabalza even had his 14-year-old son help him to direct the film. When the film wound up being too short, Zabalza filmed a few additional werewolf sequences with another (uncredited) actor in the Wolfman costume to pad out the running time, and even spliced in footage from Naschy's 1968 La Marca del Hombre Lobo.
This was the first film to involve a Yeti as the means of transforming Waldemar into a werewolf (a similar "Yeti origin" appearing again years later in La Maldicion de la Bestia in 1975). Naschy's original werewolf film had him being transformed into a lycanthrope via the bite of another werewolf (Imre Wolfstein).
Naschy followed this film up with his 1970 landmark cult classic La Noche de Walpurgis, which many film historians consider the film that started the Spanish horror boom of the seventies.