Planet of the Neanderthals Super Friends : Season 2 Episode 23

An evil scientist known as Varko devolves Earth back to a prehistoric planet and brings Neanderthals under his command to the present, which will remain so unless the Super Friends can stop him and retrieve the machine responsible for this from the prehistoric times it was placed in. With the help of Skylab, they build a time tunnel and bring his device back, restoring the world.