A group of people or an individual who hang out constantly in a common place of a dorm or apartment building, like the lobby. And will make any other person or group who attempts to use said common-area feel awkward. They have also been known to act at mental level well below their physical age. Lobby dwellers have been known to hold Magic: The Gathering sessions and will most certainly stalk you online. If you are a lobby-dweller or know someone who is, seek help by leaving the lobby for your room/apartment.
"Hey do you want to go to the lobby?"
"No, the lobby dwellers will attack us."