The Cyber Foot Mutants were originally Cyber Foot Ninja's which were injected with a dose of Krang's mutagen. They would serve the returned Utrom Shredder called Ch'rell and his adopted daughter Karai, they were used on the attack on New York.
The Cyber Foot Mutants were hidious animal like mutants which were extremly strong and deadly. Some were intelligient enough to know how to work weapons such as rocket launchers. They came in many different forms and abillities. Some were Tiger like while others were wolf and even Turtle like.
They were eventually defeated when the 1987 Turtles and 2003 Turtles crashed the Turtle Blimp onto most of them, knocking them out.