Ashiok, Nightmare Augur

+1: Target opponent reveals their hand. Choose a creature card from among them. That player exiles that card.
-2: Until end of turn, you may cast creature spells exiled by Ashiok, Nightmare Augur. You may spend mana as if it was mana of any type to cast them.
-8: Exile cards from target opponent's library until you exile a land card. You may cast cards from among them without paying their mana costs.