"I particularly liked the swim team wish," said Karyn. "Mass rape..."
What? Jon didn't rape anyone? Or did he? He made someone have sex against his will and used magic to force it again. What else could he call it? Wait a minute... he really was being that evil. Why hadn't he realized it?"
"Too bad you couldn't just take the stone yourself," said Vicki.
"If we could, it would be so much easier," replied Karyn. "Feed off of people's angst ourselves... But only a human being can use the stone... even when we're possessing these human bodies we don't count. All we can do is exert a little influence."
Okay, thought Jon. That was getting weirder and weirder. "I wish that as long as I'm invisible, nobody other than me can hear the wishes I make, including this one." He whispered his wish just in case, but the wish itself made that unnecessary.
Now what was this? Some kind of demons or spirts, or even space aliens, possessing people? And influencing Jon to make nasty wishes because they liked being around miserable suffering people? Probably even including the real Karyn, who wouldn't have at all liked someone using her body to have sex with Jon....
"I wish Karyn and Vicki would be un-possessed by whatever's possessing them, without it hurting them in any way."
Which should have worked, but....
[Author's note: if you look back you'll find some chapters which show Karyn not only saying she doesn't like Jon misusing the power, but actually thinking so, so she couldn't have wanted Jon to abuse the rock but hidden it. Being possessed is almost the only way it could happen.]