Form a Posse is a uncommon Sorcery card from Outlaws of Thunder Junction (OTJ), collector number 204. Current market price: $0.17 (foil $0.25), TCGplayer market prices via Scryfall.
Create X 1/1 red Mercenary creature tokens with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."