Todd is a large and plump mutant capybara with curly blonde hair (with a equally large mustache), blue-green eyes, a dark brown nose and large buck-teeth. He wears a pink t-shirt, a black belt with a silver buckle, blue denim jeans and brown shoes.
Todd is shown to be very cheerful, hospitable, and quite genial.
In the episode Repo Mantis, Todd is introduced as the owner of Cuddle Cakes Puppy Rescue, an amateur refuge for puppies operating out of an RV in the rural woodlands of Long Island, but has fellen behind on the payments for the RV. When Michelangelo and Donatello visited on behalf of Repo Mantis to repossess the RV, Todd greeted them with lemonade, puppies and overwhelming niceness, making it difficult for them to do their task.
Faced with making Todd and the puppies homeless, Donatello agreed to build them a new place to live, and spent the next few days making an elaborate home. Todd was deeply grateful to the Turtles, and bid them farewell as they took the RV back to Repo Mantis Salvage in the city.
In The Evil League of Mutants, Todd provides each of his teammates with lemonade upon being hired by Huginn and Muninn. The mutants' drinking of the lemonade interrupts and annoys Baron Draxum, although he later enjoys a glass himself. Todd joins the League when they go to attack the Turtles, introducing his new friends to them much to their dismay, but Todd himself does not take part in the fight. As a member of the League, Todd is described as being "as bad as they come."
Todd's Evil League affiliation does not seem to have affected his personality or his friendship with the Turtles. In the episode Nothing But Truffle, Todd and Michelangelo are shown to be close friends, though Mikey sometimes immaturely treats Todd with casual abuse or disregard.