he cracks me up

My son Mitchell has an amazing vocabulary but he sometimes has a hard time retrieving the word he wants, when he wants to say something, and he often gets words or expressions mixed up (I am notorious for this myself). He is a sweet kid and can be a pretty funny. He likes to act silly and do slapstick comedy, and loves to make people laugh. Over the years he has heard many expressions as people have told him he "has ants in his pants," is "full of beans," or is "such a card." At some point during the day yesterday he was being funny and I said "Mitchell, you kill me." Then, when Mike and the kids were dropping me off at the college, and I was closing the trunk of the van, Mitchell yelled out to me "Mommy, you break me up!"