Gruul Beastmaster is a uncommon Creature — Human Shaman card from Ravnica Allegiance (RNA), collector number 129. Current market price: $0.20 (foil $0.09), TCGplayer market prices via Scryfall.
Riot (This creature enters with your choice of a +1/+1 counter or haste.) Whenever this creature attacks, another target creature you control gets +X/+0 until end of turn, where X is this creature's power.