Mia: I'm pregnant again, Paul. I can't wait for you to come home.
Paul: I got a tree to hit on the way.
Listen up, buttercup. This joke is dark because it's about Paul Walker, who tragically died in a car accident after his Porsche crashed into a tree. The joke is that he's saying he's "got a tree to hit on the way" instead of coming home to his pregnant wife. Get it? Now go back to eating crayons.