15 Awesome Plot Twists That Totally Saved Awful Movies

13. Jason's Mother Is The Killer - Friday The 13th

The Twist: As the nubile young teens are summarily killed off throughout the iconic horror film, it's assumed that the killer is, of course, Jason Voorhees, the young boy left to drown on Camp Crystal Lake while the camp supervisors were away smoking dope and getting laid.

At the end, however, it's revealed that Jason's mother, Pamela Voorhees (Betsy Palmer) is in fact the killer, confronting protagonist Alice (Adrienne King), who gets revenge for her friends by slicing Pamela's head clean off.

Why It Saves The Movie: Even today, if you've never seen the original Friday the 13th, there's a good chance you just assume that Jason is the killer from the very beginning (just as Drew Barrymore did in Scream), but that's not the case. Compared to its main horror rivals Halloween and A Nightmare on Elm Street in particular, Friday the 13th is on the whole a pretty poor horror flick: sure, Kevin Bacon's grisly death is fun to watch, but it's an incredibly generic slasher film that does little to surprise.

At least until its ending, which confound expectations and makes the movie decidedly more memorable than it would have been with Jason stalking Alice at the finale.