Hall of Storm Giants is a rare Land card from Adventures in the Forgotten Realms Promos (PAFR), collector number 257p. Current market price: $2.03 (foil $2.56), TCGplayer market prices via Scryfall.
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}.)
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