Devouring Light is a uncommon Instant card from Ravnica: City of Guilds (RAV), collector number 13. Current market price: $0.28 (foil $0.98), TCGplayer market prices via Scryfall.
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.) Exile target attacking or blocking creature.