After Ch'rell, the Shredder attacked the T.C.R.I building which was the Utroms hideout 9 Utrom exosuits created by a Utrom bio chip were salaveged among other advanced technology the Utroms left behind.
The Foot Mechs were extremly powerful and could take a lot of damage. Although there were only 9 created, Hun was certain that just 9 could rid them of their enemies. 7 of the Foot Mechs were designed for combat and were armed with blasters and other weaponary. The other 3 were designed to look like the President of the United States, the Prime Minister of England and the Mutant Turtles Master Splinter.
The Master Splinter mech was sent into the sewers and found the Turtles pretending to be their Master Splinter and tried to force them to kill the real Splinter. However the Splinter was soon destroyed by an alien Triceraton called Zog.
The remaining Foot Mechs were deployed when the Turtles attacked the Foot HQ. Despite the Foot Mechs fighting advantages the Turtles just managed to destroy them.