The Mutant Foot Soldiers appeared in Turtles Forever.
Ch'rell the Utrom Shredder and his followers took over the Technodrome from the 1987 TMNT cartoon dimension. Besides disposing of the outdated Foot Soldiers and replacing them with more updated versions, Ch'rell also took control of the Mutagen in Krang's reserves, including the sample that mutated Hun. A vast number of Ch'rell's Cyber Foot are turned into Mutants for his use against the Teenage Mutant Ninja Turtles. The Mutant Foot Soldiers were mutated into their mutant forms without coming into contact with a living thing.