The stone morphed into a girl... of about 2-3 years of age.
"Wait!" said Jon. "I didn't mean it that way! I meant someone older. I have to wish you into something else..." He pushed the toddler away, saying "I don't want you to hear this wish, or you'll be an older girl who thinks like a two year old."
A second later, of course, he figured out that since the little girl was the wishing stone, he'd have to touch her to make the wish, and got up to go after her. She was walking out into the hall, and when Jon went there to get her, he encountered....