Jon went upstairs, his mind racing furiously what to do about the situation. It seemed that the rock would only let him swap parts or clothes with people that he could actually see. This could cause problems. Jon went into his bedroom. His dad (with his mom's body) entered the room. Absent mindedly, he picked up the rock and began playing with it.
"Jon, we need to talk" said his dad.
Jon could only think of one thing to say. "Unswap!" Nothing happened. "Unswap unswap unswap!"
Of course, because Jon's mom was downstairs, the unswap command wouldn't work.
"Jon, I wish you'd stop saying unswap!" said his dad, who, of course, had his rock in his hand.
Jon looked in horror. Now he had no way of reversing the swaps. He'd better be very careful what he wishes to swap in future.
