Basilica Stalker is a common Creature — Vampire Detective card from Murders at Karlov Manor (MKM), collector number 78. Current market price: $0.12 (foil $0.11), TCGplayer market prices via Scryfall.
Flying Whenever this creature deals combat damage to a player, you gain 1 life and surveil 1. (Look at the top card of your library. You may put it into your graveyard.) Disguise {4}{B} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)