Howling Moon is a rare Enchantment card from Innistrad: Crimson Vow (VOW), collector number 204. Current market price: $2.28 (foil $2.28), TCGplayer market prices via Scryfall.
At the beginning of combat on your turn, target Wolf or Werewolf you control gets +2/+2 until end of turn. Whenever an opponent casts their second spell each turn, create a 2/2 green Wolf creature token.