As Jon produced the wishing rock from his pocket, Karyn spoke up.
"How about a ray gun or something that makes people think its normal?"
"What?"
"Well we can swap parts, then fire a ray gun at them that makes them and anyone who sees them think their new look is totally normal! We'd never get caught!"
"Not a bad idea, but I thought something better. A device that stops time. A stopwatch, even. We can swap what we want while time is standing still, then get a long way away before restarting it and nobody will know."
"Okay, I think I understand. Let's go with that. Make the wish."
"I wish I had a stopwatch with two buttons. I wish by pressing the first button, time will stand still for everything except me and Karyn, and by pressing the other button, time will start moving again from where it stopped."
A small digital stopwatch appeared in Jon's lap.
"Nice work," Karyn noted.
"Thanks. Now let's find something to swap!"
