Hidden Cataract [The Lost Caverns of Ixalan]

Set: The Lost Caverns of Ixalan Type: Land — Cave Rarity: Common Hidden Cataract enters the battlefield tapped.{T}: Add {U}.{4}{U}, {T}, Sacrifice Hidden Cataract: Discover 4. Activate only as a sorcery. (Exile cards from the top of your library until you exile a nonland card with mana value 4 or less. Cast it without paying its mana cost or put it into your hand. Put the rest on the bottom in a random order.)