Stegmutt is a former anthropomorphic duck who was turned into a sentient, bipedal Stegosaurus.
Originally an ordinary duck, Stegmutt was mutated into his present form by the supervillain Doctor Fossil using his Retro-Evolution Gun. The rather naive Stegmutt had been enlisted as a henchman in Fossil's plans to transform the world's inhabitants into dinosaurs, in order to enable a new age for the extinct creatures. Fortunately, the good-natured Stegmutt was convinced of Fossil's evil intentions by Gosalyn Mallard and Honker Muddlefoot, and helped thwart his plans to strike the Earth with a meteor. Stegmutt was never returned to his original form, instead choosing to use the great strength given to him by his new nature for good as a part-time superhero in Darkwing Duck's team, the Justice Ducks. When not superheroing, Stegmutt works as a hot-dog salesman in St. Canard.
Behind the scenesEdit
A recurring gag in "Just Us Justice Ducks" involved Neptunia commenting that not all of the members were Ducks, with Stegmutt commenting that "[He] used to be".
An alternate version of Stegmutt appears in the episode "Darkwing Doubloon" as part of the titular hero's pirate crew. How he could have been transformed into his Stegosaurus form in this more primitive era is not touched upon.