"I wish," said Gary, "that once I leave you will forget I was here, but you will realize you were deeply in love with the old male Biff. I wish that you will be upset that you made him a girl, and I wish that you will try to figure out a way to use the stone to change him back."
"I wish that you'll want to become a girl yourself, at least partly, so you can be his. I wish that once this happens you will be completely honest with Biff about the whole situation, and while he won't be violent with you he's otherwise free to accept or reject you as he wants."
"Finally, I wish that nobody will think I'm having psychological problems. Now, goodbye."
He put the stone back, and left.
Suddenly Jon looked around. Did someone come to take the stone? No, it was still there. But somehow, Jon's thoughts went to Biff. Jon felt really bad for using it on Biff. He realized that deep in his heart he loved Biff just the way he was, even though he was a guy. He knew that the stone wouldn't reverse a previous wish, but there still had to be some way to change Biff back!