Digsite Conservator 252/291 (The Lost Caverns of Ixalan)

Sacrifice this creature: Exile up to four target cards from a single graveyard. Activate only as a sorcery. When this creature dies, you may pay {4}. If you do, discover 4. (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.)