Dirk Katar the Cutthroat

Whenever a Mountain is tapped for mana, flip a
coin. If you win three consecutive flips, you may
look at target opponent's hand. Choose a card,
and exile it face down. You may cast that card
and you may spend mana as though it were mana
of any type to cast that spell.
When Dirk Katar the Cutthroat dies or is put into
exile from the battlefield, you may put it into its
owner's library third from the top.