Ashiok, Nightmare Weaver - 188 M THS

+2: Exile the top three cards of target opponent's library.
−X: Put a creature card with mana value X exiled with Ashiok onto the battlefield under your control. That creature is a Nightmare in addition to its other types.
−10: Exile all cards from all opponents' hands and graveyards.

mythic
Legendary Planeswalker — Ashiok
From the Magic: The Gathering set Theros.