Marvin, Lich Aspirant

{x}{u}{b}{t}: Counter target spell with converted mana cost X, then exile it under Marvin, Lich Aspirant.
While a card is exiled under Marvin, Lich Aspirant you may look at the card and cast it for its mana cost. Do this only when you could cast a sorcery.
"300 feet in the air? Sounds safe to me!"
- Marvin, just before his death