A mechanic in the U.S. Army, the man known only as Litterbug was employed in the construction of the giant mutant-hunting robot Sentinels. When his mutant nature first manifested, he was forced to go AWOL. Eventually, he found his way into the small group of outcast mutant Morlocks living under the streets of Chicago. Using his knowledge of Sentinel construction, Litterbug helped the Morlocks co-opt a Sentinel unit and used it to infiltrate the local Sentinel base, which they were able to destroy. Subsequently, they fled Chicago for parts unknown. Litterbug is one of the 198 mutants who have kept their powers after the events of M-Day.