Hallowed Haunting is a mythic Enchantment card from Innistrad: Crimson Vow Promos (PVOW), collector number 17s. Current market price: — (foil $9.76), TCGplayer market prices via Scryfall.
As long as you control seven or more enchantments, creatures you control have flying and vigilance. Whenever you cast an enchantment spell, create a white Spirit Cleric creature token with "This token's power and toughness are each equal to the number of Spirits you control."