Faulty Pigeon

A hopeless outcast that can't fit in anywhere and nobody is willing to help, as in 'An unwanted streetwalker with a broken wing that nobody will feed.'

Rick: I kinda feel sorry for Mikey, he's sitting there all alone with his Hentai comic books
Jonathan: What! Mikey? Man, nobody cares about that creeper, that guy's hopeless, he's a faulty pigeon!