At the beginning of each player's upkeep, that player puts a flood counter on target non-Island land they control of their choice. That land is an Island for as long as it has a flood counter on it. At the beginning of each end step, if all lands on the battlefield are Islands, remove all flood counters from them.
![Quicksilver Fountain [Mirrodin] | Black Swamp Games](http://blackswampgames.com/cdn/shop/files/cb89c2d0-92a1-5c68-99f8-94f2d08a1b61.jpg?v=1779401027)
