Ulamog, the Infinite Gyre is a mythic Legendary Creature — Eldrazi card from Arena Anthology 3 (AA3), collector number 2.
When you cast this spell, destroy target permanent. Indestructible Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents of their choice.) When Ulamog is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.