"what'd you say to me?"

Connor has picked up this new phrase that he uses when he didn't catch what someone said, "what'd you say to me?" and every time he says it, it cracks me up because i hear it as an adult would say with attitude, even though he has no attitude at all when he says it.

Yesterday we were in the kitchen cooking while Matt was in the bedroom on his laptop and Matt said something to me, to which I replied "shut up, matt". Connor looks up at me and says, "What'd you say to my dad?" I lost it; I was doubled over busting up laughing, while Matt was in the bedroom doing the same.