Hidden Volcano

Land — Cave

This land enters tapped. {T} : Add {R} . {4} {R} , {T} , Sacrifice this land: 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.)