Overwhelm [Modern Masters 2015]

Set: Modern Masters 2015 Type: Sorcery 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. "Let the song of Selesnya be heard above the rhythm of our thundering hordes!"