Quote from Bert in the episode Spoiler: Zack's in This One
Bert: Uh-oh, that's not supposed to be there. Stuart: What just happened? Kripke: I don't know. Bert: I have a hypothesis. Stuart: I'm listening. Bert: Did you notice the thing on the back of your necks? Kripke: What? What thing? Bert: Humor me.
