Hall of Storm Giants (257) [Adventures in the Forgotten Realms]

If you control two or more other lands, this land enters tapped. {T}: Add {U}. {5}{U}: Until end of turn, this land becomes a 7/7 blue Giant creature with ward {3}. It's still a land. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)