Ghost of a Chance - S2.E44

In an environmental takeoff of A Christmas Carol, Widget is visited by three ghosts, a Viking who engaged in deforestation, an American pioneer who participated in the buffalo slaughter, and a British big game hunter who contributed to extinction of some animals. The ghosts tell Widget that they are punished until they teach a living person of their wrong acts, and Widget sees their chance for atonement when the city's mayor is making a secret deal for a polluting factory to be built.