The people who attend goodbye or birthday parties at offices for the sole purpose of eating cake. They tend to stand in the back of the group, chit-chatting among themselves, and come up with something pithy to say to a person they don't know or care too much about just so they can get out of working for half an hour or so.
Luke: Hey, are you coming to Georgia's goodbye party today? She's been downsized.
Ann: Georgia? Isn't she in... accounting?
Luke: Who cares? There's cake!
Ann: You cake vulture.