The Identity Swapping Stone

The stone he put in its place looked exactly like Jon's stone. It was the Identity Swapping Stone. It worked just like the normal stone, except that once a wish was made it changes the wisher's body to that of someone else's thus changing their identity, the wisher would remember who they used to be and would not be able to use the stone to change back, just by wishing something would they change into someone else again.