Golgari Keyrune is a uncommon Artifact card from Return to Ravnica (RTR), collector number 229. Current market price: $0.19 (foil $0.36), TCGplayer market prices via Scryfall.
{T}: Add {B} or {G}. {B}{G}: This artifact becomes a 2/2 black and green Insect artifact creature with deathtouch until end of turn.