Witchstalker is a rare Creature — Wolf card from The List (PLST), collector number M14-202. Current market price: $0.46, TCGplayer market prices via Scryfall.
Hexproof (This creature can't be the target of spells or abilities your opponents control.) Whenever an opponent casts a blue or black spell during your turn, put a +1/+1 counter on this creature.