Drink *does* turn into pee!

Sebastian, after taking a swig of his chocolate milk, announces "I have to pee!"

"So go pee then", I say. 

He starts heading toward the bathroom and then suddenly stops, turns to look at me, begins stroking an imaginary beard, and says (with considerable gravitas):

"Hmmm... So drink *does* turn into pee!"

(Quoted by Scott on Facebook)