Rakdos Keyrune is a uncommon Artifact card from Return to Ravnica (RTR), collector number 232. Current market price: $0.24 (foil $0.66), TCGplayer market prices via Scryfall.
{T}: Add {B} or {R}. {B}{R}: This artifact becomes a 3/1 black and red Devil artifact creature with first strike until end of turn.