Zex, Titan of Life's Avarice

When Zex enters the battlefield, sacrifice it
unless it escaped.
Whenever Zex enters the battlefield or attacks,
each opponent loses 3 life and you gain 3 life.
Escape—{w}{w}{b}{b}, Exile four other cards from
your graveyard. (You may cast this card from
your graveyard for its escape cost.)