The Beast of Hollow Mountain is a scifi/horror western about an American cowboy living in Mexico who discovers his missing cattle are being preyed upon by a carnivorous dinosaur. The film is notable for being based on a story idea by special effects innovator Willis O'Brien (King Kong) as well as for using a form of stop motion called replacement animation to bring the dinosaur to life. O'Brien co wrote the script under the pseudonym El Toro Estrella, O'Brien was also to have originally done the special effects for this movie but this did not happen for reasons unknown.
While the bulk of the stop motion work for The Beast of the Hollow Moutain was done with replacement animation, the close ups of the dinosaur were filmed using an articulated puppet. This was the first film with stop motion effects shot in Wide Screen and color.
The Willis O'Brien story idea that inspired the basis for his script for this film also inspired his earlier unmade script The Valley of the Mist which would later be made as The Valley of Gwangi by O'Brien's protégé Ray Harryhausen.
This film is available online as a free download.
