Jon stopped himself. He thought of doing something different than changing himself. He wanted to do something to the rest of the world.
But then, he started to imagine what it would be like. It might be a little bit much if every single person in the world transformed, especially with some sort of transformations.
And besides, the stone had a limited range. He couldn't just affect the whole world. He'd have to rig something up where the stone would teleport outside of its range and affect another area, over and over again. But if he did that, the world is a pretty big place. How long would it take to get the stone back?
Ah, well. He'd better do it. "I wish that I can reverse the following wishes at will. I wish that starting in five minutes, this stone would teleport around the world and cause transformations then return to me, limited to half the people at most. I wish that that transformation is...."