Nissa, Wise Naturalist

+2: Search your library for a land, put it onto the battlefield tapped, and shuffle your library.
-X: Target land becomes an X/X green elemental until end of turn. You gain 2 life and draw a card.
-12: Search your library for 3 basic lands and put them onto the battlefield. They become 4/5 elementals with trample and flying until end of turn.