The Fever is an ongoing conflict in the 5th level of the Ducks 3D Astral Realm Representation System. While the conflict seems to have started with the creation of the astral plane and often is put on hold, it has never had a decisive end.
The conflict is held between two forces, known as The Pink and The Mechanical and is a constant battle for domination, with the end goal most likely being elimination. The war appears to work by a form of the observer principle, in that is only takes place when someone watches, which tends to happen by accident. To date, nobody has managed to reach the site of The Fever on purpose.
The Pink is the smaller of the two forces, taking the form of a small pink house with a lawn. It is unclear how exactly it operates, but it appears to take up the defensive form in the war, being mostly untouched to date.
The Mechanical is the dominating force, taking the form of a large machine resembling intricate clockwork. Some parts of the machine are missing, being replaced by static. So far, the size of The Mechanical is undocumented, and many believe it has an infinite size, though this claim has been disputed by many researchers. The mechanical appears to try to swallow or grind up The Pink, although it has never fully succeeded in this.