Erratic Apparition is a common Creature — Spirit card from Duskmourn: House of Horror (DSK), collector number 54. Current market price: $0.14 (foil $0.18), TCGplayer market prices via Scryfall.
Flying, vigilance Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, this creature gets +1/+1 until end of turn.