Robomutts were robotic canines designed by Drek Industries to accompany the Blarg Commanders invading in Aleero City. They were fast and traveled in groups. If a Robomutt were to get close enough to Ratchet, it would rip a strand of fur right off him. New updated versions of the mutts were later designed to assist the blarg and warbots aboard the Deplanetizer.
On the Deplanetizer, smarter versions of the Robomutt were found. These Robomutts were able to find intruders by sniffing, even Ratchet in the Hologuise.