Abasi, Theif of Desires

{t}: The next time an instant or sorcery is put
into an opponent's graveyard, exile it. You may
cast it for as long as you control Abasi, Thief of Desires and use mana as though it were any color
to cast it.
Whenever you cast a spell an opponent owns,
you may reveal an instant or sorcery with equal
mana value that you own from outside the game
and put it into your hand.