James Stone is a balding 42-year-old man who went undercover at Third Street School, on the orders of Superintendent Skinner, posing as a new nine year old student in T.J. and the gang's class. He appears only in the episode "The Spy Who Came In from the Playground." He was voiced by Jason Marsden.
In his undercover outfit, James wore blue shorts, with a lighter-colored shirt, brown Sweater, Black leather shoes and white socks. He also wore a blue cap to cover his balding hair, and sunglasses to cover the wrinkles around his eyes.
The gang immediately befriends James. As time goes by the gang begins to suspect something is awry when their various secrets continue to be found out, and the gang initially blames Randall for this, but Randall denies this. The gang then finds out that Stone, not Randall, was responsible for this on the orders of Skinner.
James is compared to Benedict Arnold by the gang when they find out about the truth: while posing as a student, James wears sunglasses and a baseball cap to conceal his true identity; in the boys' bathroom, he is revealed to have stubble and be bald.
Upset over the betrayal, the gang decides to teach Stone a lesson for messing with them. By tricking him into pulling a prank on Skinner involving the flagpole, T.J. gets Randall to rat out Stone, for which Randall thanks T.J. As a result, Skinner angrily fires Stone and has him arrested. As he is taken away, Stone swore revenge on the gang.