The spirit stone

The stone put in its place looked exactly like Jon's previous stone, but it wasn't. It was the spirit stone, a stone that held an ancient spirit within it, and with each wish, the spirit would gain more influence over the wisher. Also, it will only grant wishes to one person, the one who wishes on it first, and it will always be found by the person if lost. And, it stays with them until that person dies, at which point their own spirit is trapped in the stone, to start all over again.