Ashiok, Nightmare Muse

+1: Create a 2/3 blue and black Nightmare creature token with “Whenever this token attacks or blocks, each opponent exiles the top two cards of their library.”
−3: Return target nonland permanent to its owner’s hand, then that player exiles a card from their hand.
−7: You may cast up to three spells from among face-up cards your opponents own from exile without paying their mana costs.