1 Aug 2008
You can't target a creature if its controller doesn't control an Island as you are activating the ability, and the ability won't resolve if the creature's controller doesn't control an Island as the ability resolves.
1 Aug 2008
If control of the targeted creature changes between the activating and resolution of the ability (ie, while it's on the stack), then the player who must control an Island as the ability resolves is the creature's new controller.