Jon sat wide-eyed, realizing what his errant wishing had done. Earlier that day he had wished for the stone do never get lost. He didn't realize it at the time, but this meant that the stone had become a part of him, nestled in the back of his head where no one could get to it without him dying. So, in effect, he could never actually "lose" the stone.
Of course, the unintended side effect of this apparently was that whenever he heard someone make a wish, he'd be forced to grant that wish. The stone had merged with his essence apparently, becoming a part of him. That meant any errant wish, from ANYONE could throw things off. Jon realized this, and got very worried. Someone could wish for horrible things as a simple joke, and they'd actually happen with this stone. Quickly, he tried to think of a way to undo things.
"Firstly, I wish that Zoe didn't think there was anything different about our mother." A tingling sensation came over him, confirming the wish. As he stood there and pondered what to do, not many ideas came to his head. Eventually, the phone rang.
"Jon," his now Marilyn Manson-esque mother called out, "it's Karyn!"
Jon sighed and picked up the phone. "Hello," he said, dejected.
"Hey....wanna come over and mess with the rock?" said the sweet voice of Karyn on the other end.
"We shouldn't mess with it," Jon said, "Remember what happened earlier tonight?" He briefly remembered the horror that had befallen his mother, who was now a walking poster child for Hot Topic.
"Actually, I want to try and do something about these stupid things. My back is killing me."
"I can't tonight," Jon said, "I'm too busy...you see..."
Karyn never let him finish. "Oh come on Jon. I just wish you'd come over here right now." Jon cringed as he felt the tingling sensation wash over him...
