Horyxik, Dark Dealer

{1}, {t}: Target opponent may have you mill the top card of your library into exile. If they do, they may play that card until the beginning of their end step without paying for its mana cost. If they cast it this way, you gain X life and draw X cards, where X is the mana value of the exiled card. If at the beginning of that players end step, that card remains in exile, that player loses X life, where X is the mana value of the exiled card. Then, place it in your graveyard. If that player didn't have you