Tales From The Cryptkeeper
Season 1, Episode 08
Extreme skateboarder dude Peter is fascinated by the perfectly preserved Neanderthal caveman that his scientist father has on ice at his laboratory. When he's left alone on his birthday, Craig accidentally unleashes the pre-modern man, and a whole lot of havoc along with him.
Honestly, there's very little menacing about the caveman. He immediately steps into the role of the lovable lug, and Craig teaches him how to wish him a happy birthday, dresses him up as his father, and has him accompany him to the amusement park almost instantly upon their first meeting.
Not even a hint of fright here, or any real monsters to speak of, so this scarcely qualifies as prime Tales From The Crypt material. It could have been an episode of any Saturday morning cartoon with just a few character design changes.
Really lightweight, like Encino Man for children. Buuuu-dy.