"Here's the rules," Mxy said before they could get sidetracked. Bat-Mite was his best buddy but he had a tendency to be scatter-brained. "You've changed bodies for forty-eight hours." He brandished a watch marked, improbably, up to "forty-eight o'clock." "You have to live each others' lives for that long. And if anyone guesses about the switch, the change will be...permanent."