Enigma Sphinx [Alara Reborn] Centaur Archer but Tributes are required for

but Tributes are required for monsters level 5 or more

his spectral guardians kept vigil

instead it's turned face up and assigns or deals damage

Set: Shadows over Innistrad Prerelease Promos Type: Sorcery Rarity: Mythic Cost: {4}{W}{W} Exile all creatures

Enigma Sphinx [Alara Reborn] Centaur Archer but Tributes are required forSet: Alara Reborn Type: Artifact Creature Sphinx Rarity: Rare Cost: {4}{W}{U}{B} Flying When Enigma Sphinx is put into your graveyard from the battlefield, put it into your library third from the top. Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom of your library in a random order.)