"I wish Zoe was naked and desperately wanted to fuck me," Karyn said, with a smile.
Jon looked shocked, realizing what a horrible thing his friend had just done (although, in retrospect, Jon's original wish wasn't really too different). Zoe just looked confused. She didn't know about the wishing stone (or stones), so she had no idea that Karyn's wish would actually come true.
But again, this was The Substitution Stone, so Karyn's wish wouldn't be granted the way she intended it to. Instead, her wish was changed to ...