Yo, you have the biggest Oliver brain, which means you are the dumbest boy ever.
Oliver Brain
Explanation
Explain Bear
Listen up, buttercup. This joke says you got a big "Oliver brain," which ain't a good thing. See, they're saying your brain is as big as Oliver's, and since Oliver ain't known for being sharp, that means they think you're dumber than a box of rocks. Ouch.