Legendary Creature — Eldrazi
7 / 7
When you cast this spell, target opponent exiles the top half of their library, rounded up.
Ward—Sacrifice two permanents.
Ulamog, the Defiler enters the battlefield with a number of +1/+1 counters on it equal to the greatest mana value among cards in exile.
Ulamog has annihilator X, where X is the number of +1/+1 counters on it.
Annihilator abilities trigger and resolve during the declare attackers step. The defending player sacrifices the required number of permanents of their choice before they declare blockers. Any creatures sacrificed this way won't be able to block.