A joke doing the rounds in Hollywood back in the mid- to late-80s inspired the 1987 classic Predator. The joke went that after four gruelling Rocky movies, the scrunch-faced boxer would have to fight an alien if they were ever to make a Rocky V. Predator creators Jim and John Thomas liked the idea so much they substituted Rocky for Dutch and created one of the most beloved sci-fi franchises of all time.
But much as the idea worked, the path of the Predator on the big screen has been a perilous one since. Predator 2 brought one of the hunters to the big city in futuristic LA that seemed to eerily prophesy the lawlessness of the LA riots, which would happen a few years after the film came out. But something didn't quite gel and it felt so far removed from the first as to put the Predator franchise on ice for years afterwards. A rumoured third film, which would have been set in the 18th Century, never materialised.
The Predator has appeared on screen since, in two risible AvP movies, but it was only just post-Predator 2 that Robert Rodriguez was first commissioned by Fox to write a third film, and he imagined a Predator movie that brought the action back to the jungle and multiplied the scale a hundred times over. Some 15 years later, Fox dug his script out of storage and set him to work.