Windom Earle

Ward—Discard a card
{t}: Exile the top card of each opponent's library
face down. For as long as those cards remain
exiled, you may look at them.
Whenever an opponent casts a spell, you may
reveal a face down card exiled by Windom Earle.
If that card shares a card type with the spell, cast
it without paying its mana cost.