The "Sewer Worker", as he appeared in the end credits, used to be a recurring minor character in the series.
- Leatherhead and interviewed by Joan Grody. - He's attacked by
- Technodrome prepares to mutate the world. - He's seen running with everyone-else in New York as the
- Squirrelanoid at the end. - He finds a bag of popcorn and is attacked by a
- Fungus Humungous's fear spores and appears running in the sewers afraid of a "giant mutant squirrel." - He gets exposed to
- Antonio's Pizzeria commercial being controlled by one of Pizza Face's minions. He later appears in Antonio's Pizzeria helping prepare his calzones. - After being zombified he appears in the
- Ninja Turtles fighting Rocksteady and Bebop, and gets hit in the face with a canister of mutagen (which Bebop intentionally threw at Michelangelo) while investigating it. As the result of falling off the building and into the dumpster, he mutates into a humanoid mutant made entirely out garbage with a banana peel cap, with a disgusting mouth capable of spewing slime, control over garbage and dissolving abilities that the press dubs "Muckman". Muckman is convinced by Joe, his eyeball, to be a hero when he finds the Purple Dragons mugging a man and manages to beat them up. The man witnesses the action and makes it to Joan Grody's show, becoming New York's new sensation. When the Turtles and April find Muckman and Joe Eyeball, Muckman blames the Turtles for his mutation yet both groups had to leave before Joan Grody could get a full glimpse of the Turtles. Upon seeing the news of Muckman, Rocksteady and Bebop plan to take advantage of this and look for him. When Rocksteady and Bebop find Muckman, he thinks they are with the Turtles until they claim that they aren't with them. He asks if the Turtles mutated them too and they says yes. Muckman is convinced by Rocksteady and Bebop to help rob an abandoned Kraang Hive Mind lab claiming it contains a cure, though Joe Eyeball becomes suspicious of Rocksteady and Bebop's motives. The Turtles catch up to them as Muckman begins to attack. Bebop tells Muckman to get the chemical while he and Rocksteady dealt with the Turtles. Muckman joins the fight and the Turtles are defeated. The Turtle try to reason with Muckman but they are all knocked out by Bebop's grenade. Rocksteady throws Muckman into the lab and is blasted by Kraang traps. Muckman finds the chemical and is blasted by another trap. Rocksteady takes the chemical from Muckman who is then helped by the Turtles. Muckman shoots slime at Rocksteady and Bebop, who retreat when the chemical explodes. Muckman covers up the Turtles' existence by telling Joan Grody that they were just people in costumes like the Pulverizer. - Garson Grunge is seen working as a garbage man when he hears a commotion involving the
- Annihilation Earth! Part 1 - Muckman participates in the battle against the Triceratons.
- Annihilation Earth!, Part 2 - When the Triceratons activate the Heart of Darkness, Muckman is among those sucked into a black hole.
- Earth's Last Stand - Thanks to the Turtles' interference, the Heart of Darkness didn't go off keeping everyone among the living.
As Muckman, he sports a ripped-up jumpsuit, a banana peel on his head, and a sewer cover on his left foot.
"Aargh! Giant mutant Squirrel!"
"Obey the flavor."
- Before Muckman's debut, there was a horror movie poster of a Muckman movie in Michelangelo's bedroom.
- Muckman's appearance and the title of the episode he officially debuts are a nod to The Toxic Avenger, a low-budget 1984 film which spawned several sequels and an animated spinoff, produced by Playmates, who also made the original line of Ninja turtles toys.