Wizard's Retreat

{t} Add {c}
Whenever a permanent or spell you control becomes the target of a spell, if Wizard's Retreat is in your hand, graveyard, or in play, you may pay {6}{u}{u}. If you do, exile the top four cards of your library, and you may play
a nonland card exiled this way without
paying its mana cost. If you play a card this way, exile Wizard's Retreat.