Horror franchises aren’t exactly known for their rigorous worldbuilding. With enough time, the story inevitably devolves into the absurd as each sequel tries to outdo the rest. That’s how we end up with a Druidic cult in a Halloween movie, “dream demons” in A Nightmare on Elm Street, and the Illuminati in The Texas Chainsaw Massacre.
But no film franchise has gone quite as wild as Friday the 13th. Even though the first movie confirmed that Jason Voorhees was, in fact, just his grieving mother, Pamela, the sequels brought Jason back as an immortal zombie. Over time, this devolved into some of the strangest choices in horror movie history, including an odd body-swapping element involving slug-like parasites and even sending Jason into space.
