Joe Eyeball was the sidekick of Muckman. Originally known as Joe Junkee, both he and Garson Grunge were two garbagemen who had been mutated by Bebop and Rocksteady when they poured Mutagen out a window. They took the names Muckman and Joe Eyeball. The pair were at first enemies of the Turtles because they blamed them for their accident.
April and Irma scoured the city in search of the two missing garbage men. When they fond their garbage truck, April contacted the Turtles, only to find themselves face-to-face with Muckman and Joe Eyeball. The Turtles track April and Irma to the alley behind Tropotron Labs but as soon as they get close to the two new mutants in town, they suddenly become very weak. In their weakened state, the Turtles are unable to save April and Irma and they are carried off.
Elsewhere, Shredder, Rocksteady and Bebop had returned to the Earth's surface. They locate Muckman and Joe Eyeball and convince them that the Turtles mutated Bebop and Rocksteady. The two groups than form an alliance.
However, the Turtles track April's Turtlecom to discover that Muckman and Joe Eyball have teamed up with Shredder. As soon as Muckman and Joe Eyeball get close, the Turtles collapse. Splinter arrives and is taken prisoner by Bebop, Rocksteady, and Shredder who prepare to return to the Technodrome. Shredder leaves the unconscious Turtles to Muckman and Joe Eyeball.
But they eventually helped them rescue Splinter from Shredder, after discovering that Bebop and Rocksteady caused their mutation. Joe, having developed feelings for Irma, gave her a chunk of slime to remember him by. After Shredder and Co. had been defeated, Donatello said that he might be able to find a way to make him and Muckman normal again, but Muckman told him to take his time as they were now mutant heroes.