After Dr. Ivo Robotnik had launched a successful coup and began consolidating his power, Muttski and Chuck were captured and Roboticized during Charles' time running a Chili Dog Stand. Muttski remained an emotionless automaton until his liberation following Robotnik's death at Sonic's hands, and later Deroboticized by the Bem, coming to live with Sonic and Uncle Chuck, as well as Jules and Bernie, in Knothole. Muttski's bond with Sonic strengthened following his return from space, where, courtesy of the alien implant Sonic had installed to be able to translate alien languages, Muttski's normal inaudible woofs were translated into proper speech, allowing Sonic to communicate with him and understand responses. Following the destruction of Knothole, Muttski continued to reside in New Mobotropolis with Sonic's family, right up until the Super Genesis Wave changed the world. (StH: #43, #50, #123, #134, #175, #247)
Muttski is Sonic's devoted pet and close friend, and is very much attached to the rest of the Hedgehog family. He was also quick to befriend Tails, and was apologetic upon learning that he had scared Tails while playing a game with him.
- Muttski is one of several characters to originate from the SatAM cartoon show, where he appeared only in the pilot episode in his Roboticized form.
- When Muttski "spoke" while still a Mobini, he is shown to speak in third-person like: "Muttski is happy to have you home again." instead of "I'm happy to have you home again."