Chord of Calling [Magic 2015]

Set: Magic 2015 Type: Instant Rarity: Rare Cost: {X}{G}{G}{G} Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)Search your library for a creature card with mana value X or less, put it onto the battlefield, then shuffle.