Shadow Alley Denizen is a common Creature — Vampire Rogue card from Gatecrash (GTC), collector number 76. Current market price: $0.22 (foil $0.97), TCGplayer market prices via Scryfall.
Whenever another black creature you control enters, target creature gains intimidate until end of turn. (It can't be blocked except by artifact creatures and/or creatures that share a color with it.)