Usually a homeless or drug-seeking person who waits in parking lots to acost people for money while they get out of their vehicles. Uneasily detered, they shamble from one car to another much like the living dead.
Man to wife: Oh shit Mary, roll up the window. It's a parking lot zombie!
Wife to man: Oh Harold, I am scared of his staggering gait, his lip smacking, and his wild-eyed stare!
Man to Parking Lot Zombie: (gesturing to an empty wallet)
Parking Lot Zombie: ahgggghhhhhhhuuuuuhhhhhhh(Spots a Lexus SUV pulling up to the Walgreens and heads towards it)
Man to wife: Hurry up and get into the store! Move it! Move it!