While Piranha 2: The Spawning may have received terrible reviews, the monster sequel still played a pivotal part in movie history when it inspired director James Cameron’s The Terminator. The Terminator is often thought of as James Cameron’s first big hit, and the sci-fi horror is the movie that made him a major blockbuster helmer. However, before Cameron had ever even met with Terminator star Arnold Schwarzenegger, he had already directed another, often-forgotten horror movie.

While 1978’s Piranha received surprisingly solid reviews and was singled out by Steven Spielberg as the “best of the Jaws rip-offs,” that creature feature had a great script by John Sayles and the assured direction of Joe Dante to buoy its meager budget. When it came time to produce a Piranha sequel, the studio opted to go for the cheaper alternative of hiring a young, unproven director in the form of James Cameron. Then 27, Cameron was only offered the opportunity to direct Piranha 2: The Spawning when the original helmer left due to creative differences.

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The critically-derided sequel was Cameron’s first movie - which he was eventually fired from by the producer - and he was so burnt out by the experience of Piranha 2: The Spawning that he contracted a fever while suffering exhaustion. It was then that the original villainous T-800 came to Cameron during a fever dream, with the stress of making the monster movie unintentionally inspiring the director’s later hit. Cameron envisioned, as he later described it, "a metallic torso holding kitchen knives dragging itself from an explosion" during a nightmarish vision, and thus the Terminator franchise was born. The image would go on to inspire the script of The Terminator, and the success of the first film would lead to two direct sequels, three reboots, and a television show.

Piranha 2 and The Terrminator

However, this was not the only time the critically-dismissed Piranha 2: The Spawning helped the Terminator franchise. Cameron was originally set on casting the Police frontman Sting as Kyle Reese in The Terminator, and would likely not have considered the much less famous Michael Biehn were it not for Sting’s blunt reaction to Cameron’s earlier credit. When offered the role, Sting derisively noted the title of Cameron’s first movie and made it clear he had no faith in The Terminator’s potential. It was a prediction that would prove ironic when the Terminator proved a huge hit the same year that Sting’s sci-fi adventure Dune, an ambitious David Lynch production, flopped at the box office.

Between ensuring that Cameron avoided stunt casting despite his best attempts and giving him the fever that inspired the original movie, Piranha 2 ended up being responsible for much of The Terminator's sleeper hit success. This may have made up for the sequel's abysmal reception, although The Spawning is still firmly James Cameron’s worst horror movie. That said, the monster sequel is still a pivotal piece of cinema history thanks to Piranha 2: The Spawning’s outsized, unintentional influence on the Terminator.

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