Ordruun Mentor is a uncommon Creature — Minotaur Soldier card from Ravnica: Clue Edition (CLU), collector number 39. Current market price: $0.19, TCGplayer market prices via Scryfall.
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) Whenever you attack a player, target creature that's attacking that player gains first strike until end of turn.