Blackstar, Master Mage

When you cast Blackstar, Master Mage, reveal the top X cards of your deck. Then, you may cast an instant or sorcery from among them that costs less then the amount of mana spent to cast Blackstar, Master Mage. Shuffle any remaining revealed cards back into your library.
{x}{u/r}: Return target instant or sorcery from your graveyard to your hand, where X is that card's mana value.