"You really can't tell?" Jon asked, with a big grin on his face.
Karyn looked around the room carefully. Everything looked exactly the same. Patting herself down revealed no changes either. "I don't see any differences at all." Karyn said. "What did you do?"
"Amazing! Okay, I will give you a hint, I changed something about your body"
Frantically, Karyn made an inventory of her body.
After looking at herself every way she could in the mirror, she couldn't find anything changed. Of course, it would be easier to concentrate if Jon wasn't rolling around on the floor laughing.
"Okay, Jon, I give up, what did you change?"
Jon finally managed to stop laughing enough to say "I wish Karyn remembered how her body used to be before I made my last wish." Of course, the resulting shocked look on Karyn's face was enough to start Jon laughing again.