Ulamog, the Defiler

When you cast this spell, target opponent
exiles 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.