Blood Hound is a rare Creature — Dog card from Mercadian Masques (MMQ), collector number 176. Current market price: $0.48 (foil $2.57), TCGplayer market prices via Scryfall.
Whenever you're dealt damage, you may put that many +1/+1 counters on this creature. At the beginning of your end step, remove all +1/+1 counters from this creature.