Overwhelm [Magic 2015]

Set: Magic 2015 Type: Sorcery Rarity: Uncommon Cost: {5}{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.)Creatures you control get +3/+3 until end of turn. The Conclave acts with a single will, expressed by countless warriors.