Jon thought, as he walked, about what he'd done over the years. Seeing the results in the reddish skies, quickly shifting hues, the streets which seemed to sing of better times. Everyone knew his name, but not everyone knew why. Karyn hadn't known his true reason for trapping the stone within his chest.
I wish the stone was able to draw on everything inside me to amplify its power and affect the entire world.
Always, always, the stone slowly drained him, in preparation for the next wish. He couldn't stay awake for very long lately, and those hours he could were spent dragging himself along. It would not have mattered whether his next terrible wish had been before or after the stone became part of him. The memory came as clearly to him as if it had happened right after he left the empty house.
Jon sat in his room, reading and thoroughly enjoying an RPG book he'd gotten. More and more, he found himself wishing the world was like that. It was set in the real world anyway... mostly. Then it came to him. He felt like hitting himself. I wish the world was like that. The stone pulsed within his chest, and Jon felt a powerful wave force itself out of him, spreading in all directions.
Both of those wishes could have ended up so much worse, but as time went on, the stone had begun granting his wishes in a way that was initially beneficial. But only initially. Whether this was intentional, or misguided well meaning, Jon didn't know. He supposed it didn't matter. The outcome was the same.