Revenge of the Nerbs
While attempting to steal power from Robotropolis, the Freedom Fighters are caught in an electric force field. And before the Swatbot Armada can come to claim thier prize, the Freedom Fighters escape through a hole in the ground dug for them by a Nerb, part of an underground-dewlling nasty acting, ungrateful race of underground nerds. The King Nerbs maintains that contact with surface-dwellers is bad news, but their air vents and water supply are being threatened by construction activity above ground. The Freedom Fighters, now disgusted head towards the surface and discovers one of the old Mobian sewer pipes and come to find Robotnik doing some excavating to build an new underground installation and 3 Nerb prisoners!