A person(s), usually one of your friends, who goes onto your Facebook after forgetting to log out and abuses the "add friend" button on a lot of random people. Alcohol may be a factor in some of these cases, and depending on the severity, the damage may be irreversible.
Besides adding random people the friend(s) may also "like" unwanted fan pages (Mike the Situation, Adam Lambert, etc.), send inappropriate inbox messages to the opposite sex, make self-degrading status updates, fool around on Facebook chat, and change relationship status.
Symptoms of a Facebook Vulture attack include many notifications, inbox messages entitled "do I know you?" or "What the fuck?". One may commence in the the speedy canceling of friend requests, status updates, fan pages, etc, in an attempt to alleviate some of the pain, however the damage is already done.
My Facebook the next morning after a party: You have 50 notifications. Brent likes your status: "I shit the bed!" 10 unread inbox messages: "Do I know you?" "Who the fuck's this?" "Facebook Vulture attack?" (Ok maybe that last one was a lie, but I'm hoping the word catches on) Megan likes your status: "I <3 the Hanson brothers!"