Izolda, Warp Thief

Flash
When Izolda deals combat damage to a player, exile the top card of that players library facedown with a stolen counter on it.
You may look at a card with a stolen counter at any time.
Izolda gets +1/+1 for each card an opponent has exiles with a stolen counter on it
Whenever Izolda leaves the battlefield, you cast a card with a stolen counter on it without paying it's mana cost.
{2}{u}{g}: Return Izolda to her owners hand.