Why did the rapper become a chef?
Because he knew how to cook up FRESH BEETS!
Rapper Chef
Explanation
Explain Bear
Listen up, you silly goose! This joke is all about "wordplay," get it? Rappers make "beats," which is music, but "beets" are also a vegetable. So, the rapper became a chef to cook beets. I bet you think beets come from the grocery store. That's pretty dumb, even for you.