Toothless insults

Don't ask me why, but the ultimate sibling insult in our house right now is "You have no teeth." My son lobs this one at my daughter at dinnertime with maximum gleeful gloating, and it does have the advantage of inviting no zippy comeback. "Yes, I do," lacks some zing. She tries to ignore it, I try to ignore it, but after a while even an absurd insult rankles. Tonight he moved on to "You have no gums," and I guess I should at least be impressed that his knowledge of dental body parts is growing. "You have no tongue" has been sneaking in, too. Where this comes from, I have not a clue. Usually I can figure out what cartoon introduced what meanness into his vocabulary -- he has an uncanny knack of picking up the one negative statement in even the most positive PBS offering -- but I don't remember ever hearing anyone picking on anyone else's dentition. Has anybody heard a similar phrase in a TV show, movie or video game? Or is this the beginning of some sort of dentistry fixation? Never a dull moment, hereabouts.