Las Noches del Hombre Lobo

Las Noches del HombreLobo, also known as Nights of the Werewolf and Nights of the Wolfman, is a 1968 Spanish horror film that is the second in a long series about the werewolf Count Waldemar Daninsky, played by Paul Naschy. It is considered by some to be a lost film. It has come to be referred to as the second of theWaldemar Daninsky werewolf movies. However, there are serious doubts as to whether the film was actually made no one including Naschy himself has ever seen it. It apparently was never theatrically released, nor has it ever turned up on video.

Seeing how this is a lost film, little is known about its plot. All that is known of it, as mentioned by Naschy himself, is that the story deals with a professor who learns that a student of his suffers from lycanthropy, and under the guise of helping him, uses him as an instrument of revenge by controlling him by means of sound waves when he transforms. It is possible this film later somehow became the 1970 FURY OF THE WOLF MAN as the plots of the two films are very similar, and that would explain why NIGHTS no longer exists. Someone on a fan site claimed they saw a still photo from this film, but it could have actually been a still from Fury of the Wolf Man with a variant title printed on it by the distributor, especially since Fury was only theatrically released five years after it was madeAnother Naschy film, El Retorno del Hombre Lobo, was recently released on DVD as Night of the Werewolf, causing confusion between the two films. Nights was followed by the third film in the series in 1969, Los Monstruos del Terror. ........

Source: Wikipedia