Garruk's Rooftop Vulture

Flying When this creature dies, you may put target Zombie card from your graveyard on top of your library.

You may pay rather than pay the mana cost for Zombie creature spells you cast.

Trample Play with the top card of your library revealed. You may cast creature spells from the top of your library. (Do this only any time you could cast that creature spell. You still pay the spell's costs.)