Elizabeth, Royal Descendant

When Elizabeth enters the battlefield, look at
target opponent's hand. You may exile a nonland
card from it. As long as that card remains exiled,
its owner may play it. A spell cast this way costs {4} more to cast.
{w}{u},{t}: Exile up to 2 cards in graveyards.
{w}{u}{b}, return an unblocked attacker to hand:
Exile Elizabeth, Royal Descendant, then return
her to the battlefield transformed, tapped and
attacking, under her owner's control.