Suddenly, as the stone flashed white, information flooded into Jon's mind with magical certainty. Specifically the words, 'You are not Jon Gibson'.
"What do you mean I'm not Jon Gibson!?" Jon asked the stone in indignantly. "What are you talking about, Jon?" Karyn asked, confused. "This" Jon gestured to the rock in his hand, "Just said I wasn't Jon Gibson when I wished for it to tell me something." Jon's mind was boggling at what that meant, was he adopted or something? Karyn scratched her chin thoughtfully before her eyes shot wide in sudden realization. "Holy shit!"
"What?" Jon asked.
Karyn looked shaken, "So everyone besides you and me thinks I always had these," she pointed at her new boobs and hair, "it's like it's always been that way. What if someone made a wish that changed you and you don't remember who you used to be?" Jon opened his mouth to argue, but found he couldn't absolutely refute it. He remembered his whole life as Jon, but with the stone, how could he be sure.
"What, what do I do?" Jon asked. "Don't freak out!" Karyn exclaimed, putting a comforting hand on his shoulder, "Maybe someone just changed your name because it used to be something dumb like Eggbert. Why don't you wish to know who you're supposed to be, and then we can figure out how to fix whatever's happened."
Jon took a deep breath and made his wish, "I wish I knew who I was originally, and why I'm now Jon Gibson."