Xana, Dragon Caller

Haste
{u}{g}, {t}: Look at the top card of your library.
If it's a land card, you may put it onto the
battlefield tapped. If you don't put the card onto
the battlefield, put it into your hand. If this is the
third time this ability has resolved this game, you
may summon Xira, the Ancient. (You may put
Xira, the Ancient into play from your exile zone.)