The Caveman (S01E09)

Tired of the constant noise from passing cars outside his home, Mr. Benn visits the costume shop. Dressed in a caveman's fur, he finds himself transported to a prehistoric world, where he encounters a tribe of cavemen crowded into small caves. As Mr. Benn questions why they don’t relax on the grass outside, he barely escapes being crushed by a rushing herd of dinosaurs. The cavemen explain their need to stay in the caves due to a lack of other options, prompting Mr. Benn to offer them a lesson on construction techniques.