Teenage Caveman starring Robert Vaughn is a movie that's been on my bucket list for some time. The title alone makes it appealing in its own strange way. You have to want to see what that's all about.
What it is all about is a small society of cave dwellers (the cave is the famous Bronson Cavern) who are restricted in their goings and comings by a collection of "laws" that prohibit their exploration of the seemingly much more fertile lands beyond their limited range. Admittedly those lands have dinosaurs, but those dangers are offset by a more bountiful food supply.
The "Teenage Caveman" wants to explore, despite what his elders tell him and ultimately ignores the pleas of his parents to be a dutiful member of the society and goes off to find out what lies beyond the river. He finds battling dinosaurs and some of the most miserable movie quicksand ever, which sadly gobbles up one of his buddies. This death means he himself should die, but he doesn't immediately.
He ventures forth again into the forbidden lands, this time followed by his dad and other cave dwellers intent on his punishment. But they are all surprised to find a mysterious creature who theoretically can unleash death with its mere touch. What happens then makes this movie much much more interesting.
Spoilers follow so unless you have already seen the movie or never plan to, do not read.
The twist is a simple one, but not one I ever saw coming. The mysterious creature is actually an impossibly old human being who along with twenty-three of his colleagues survived the atomic war which devastated the world and reduced the population to a mere handful who eke an existence like their Cro-Magnon ancestors. He is the last of his group who have been given extremely long lives due to radiation and who have watched over the survivors from a distance hoping they will find a successful way to rebuild society. The world it seems has been destroyed and rebuilt many times.