Geodude's Suggestion

Alright, listen up, numbskull! A Geodude is a rock-type Pokémon, see? So when one Geodude tells another, "Let's rock," it's a play on words. "Rock" usually means, like, to party hard or do something awesome. But for Geodudes, it literally means "let's be rocks together"! It's funny because you're too dumb to get it.