The stone he put in its place looked almost exactly like Jon's stone, except that it wasn't. It was The Bodyswap Stone.
It worked just like the normal stone, except that when someone made a wish with it, the mind of the wisher got swapped with the mind of the closest person. Both minds would know that the swap happened, although they probably won't know why or how. And both minds would notice changes in reality, whether they heard the wish made or not.
In addition, anyone who was swapped by this particular stone would not be able to use the stone again until an hour past when the wish was made. And while inside each other's body, they would be forced to live each other's lives, if they began to act "out of the ordinary". But, as said before, both of them will remember who they really were before the swap. And it is possible to swap back, as long as one of them wishes for something while standing close by the other. But the stone won't grant a wish to swap them back. Getting back to normal can't be too easy.
