10 Dumb Movies With Genius Plot Twists
8. The Killer Was Jason's Mother - Friday The 13th
As much as the original Friday the 13th is an indelible staple of the slasher genre, it's also not the sharpest knife - or, er, machete - in the drawer.
When you compare it to genre forebears such as The Texas Chain Saw Massacre, Black Christmas, and Halloween, Friday the 13th isn't just low-effort and lightweight, it's also a low-IQ movie chock with outrageously bad dialogue and inane, grating characters.
But it earned its place in genre royalty thanks to its incredible twist ending.
After viewers spend the entire movie assuming that a resurrected, pissed off Jason Voorhees is the one slaughtering Camp Crystal Lake's unfortunate campers, the final reel reveals that the killer is actually Jason's murderously vengeful mother, Pamela (Betsy Palmer).
The real beauty of the twist is that it still works today - casual horror fans will forever associate the series with a hockey mask-wielding Jason above all else, and so the mother bait-and-switch continues to catch unsuspecting viewers unawares.