Ysera, the Dreamer

Flying, Trample
Whenever Ysera, the Dreamer, deals combat damage to a player, exile the top 2 cards of your library face down with 2 dream counters.
During your upkeep remove a dream counter from all cards exiled by Ysera. When a card exiled by Ysera has no dream counters on it, you may cast it without paying its mana cost.