Summon Durnehviir

Spree (choose one or more additional costs)
Dur + {b}: Lose 1 life, Sacrifice a creature then draw two cards.

Neh + {b}{g}: Search your library for a card named Durnehviir, reveal it and put it into your hand, shuffle your library.

Viir + {b}{b}{g}{g}: Search your library and/or graveyard for a card named Durnehviir, reveal it, put it onto the battlefield, Shuffle.