Cave of the Frost Dragon is a rare Land card from Adventures in the Forgotten Realms (AFR), collector number 253. Current market price: $0.39 (foil $0.52), TCGplayer market prices via Scryfall.
If you control two or more other lands, this land enters tapped. {T}: Add {W}. {4}{W}: This land becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.