In the final scenes of the films, the killer (played by Betsey Palmer) has hacked to death everyone at the camp to avenge the drowning of her mentally disabled son Jason, except for Alice who is the lone survivor, who battles the killer on the beach.

But when Alice finally grabs the machete, she is able to vanquish her assailant once and her for all.

The killer gets her head chopped off. The Queen of the Slashers gets a death worthy of a queen.

At this point an exhausted Alice collapses into the canoe and drifts into the lake under the guiding light of the full moon.

As night turns to morning on the placid lake, we are greeted by the most beautiful music I have ever heard in a horror film. Something about film cameras in 1979 made the gorgeous green, orange and pink colours of the changing fall leaves and their reflection on the lake just pop. As the police approach on the shore, we know Alice is going to be all right, and…

BAM!

Just when we least expect it, the corpse of Jason (the killer’s son who drowned decades earlier) pops out of the very lake he drowned in to drag Alice to her death.

Cut to Alice screaming in a hospital bed. Apparently it was all a dream. Or was it? The police found her floating in the lake, put didn’t find the boy she claimed pulled her in, with Alice strangely saying “then he’s still there.”

Still there meaning his corpse is still at the bottom of the lake where he drowned decades earlier, or still there, meaning a zombie is still on the loose? It’s all left so beautifully ambiguous as we cut once again to a shot of the beautiful lake and its majestic Fall colours. Cue beautiful music.

Apparently, the idea of the final jump scare came from a producer who had just seen Carrie (1976) which had ended with a similar dream jump scare, where the heroine visits Carrie’s grave, only to have Carrie’s arm reach out from beneath the ground:

But when Friday the 13th quickly became one of the most successful horror films of all time with lineups around the block, the film’s producers began demanding a sequel that continued the story.

Continued what story? The killer was beheaded and Jason returning from the dead was just a dream. But the producer’s wanted Jason to come back so part 2 opens with Jason stalking Alice at her own home a couple months later, and what makes this so creepy is he’s suddenly a grown man.

So while Alice being pulled into the lake by the zombie of an 11-year-old drowned boy was just a dream, it foreshadowed an even creepier reality: Jason never drowned at all but survived in the woods all those years and was now a grown-ass man wanting revenge for the beheading of his mother. I think that’s absolutely brilliant, but the creators of the original film thought it was the dumbest idea they ever heard and had little to do with the sequels.

Nonetheless when they saw all the money the franchise would gross with 10 sequels, and a remake, a brief TV show and video games, novels and comics, original screen writer Victor Miller, who was only paid perhaps 5 figures in 1979, sued to gain rights to the series. The judge gave him ownership of Jason as a child, but not the hulking hockey masked homicidal maniac he’d become as an adult.