A mockbuster (also known as knockbuster or a drafting opportunity) is a movie created with the intention of exploiting the publicity of a major movie with a similar title and/or subject. Mockbusters are often made with a low budget. Unlike films which are produced to capitalize on the popularity of a recent release by adopting similar genre or storytelling elements, mockbusters are generally produced concurrently with upcoming films, and released direct-to-video at the same time the real film reaches theaters or video outlets. A mockbuster may be similar enough in title, packaging, etc.in hopes that consumers confuse it with the actual film it mimics, but their producers maintain that they are simply offering additional products for consumers who want to watch additional films in the same subgenres.
Mockbusters have a long history in Hollywood and elsewhere. For example, the 1959 Vanwick film The Monster of Piedras Blancas was a clear derivative of Creature from the Black Lagoon, complete with a creature suit by the same designer, Jack Kevan. Attack of the 50 Foot Woman spawned Village of the Giants; The Land That Time Forgot spun Legend of Dinosaurs & Monster Birds.
Such films tend to fit the classic B movie model, produced on a small budget and derivative of the target film and other similar projects. The reduced costs made available by using modern video and computer graphics equipment, and the tie-in to the mainstream film's advertising, has allowed the mockbuster to find a profitable niche in the home video market. Blockbuster, at one time one of the largest DVD and video-game rental chains, gave implied support to the concept by buying 100,000 copies of The Asylum's version of War of the Worlds in time to coincide with the theatrical opening week of Steven Spielberg's film based on the same novel starring Tom Cruise.