For most people, having no parents would mean they ceased to be. Fortunately, Fred had more wishes to make, so the wish was interpreted in a different way.
Suddenly...the room was empty...well, not literally so. All his stuff was gone. The room looked like it belonged to someone else. Even the pencil he'd had in his hand had vanished.
Unknown to him...he had wished himself out of existence. There was no such person as Fred Orr anymore. His parents weren't his parents. He still existed, obviously...but he had no parents...at least not ones who claimed him.
He suddenly heard a scream, and turned. There was a kid his age standing there. "What are you doing in my room?"
Nothing in his wish had said the Orrs couldn't have a child...just that he didn't have parents. And, since the wishes didn't end or create life, this stranger must have come from somewhere.
Fred didn't know any of that. He just knew that all of the sudden, his room changed, and this other person was there.
