Stu is Buster Baxter's uncle. He‘s a tan rabbit who appeared in "Ungifted." In that episode, Buster finds a model called "The Grain Reaper" that belonged to Stu. Buster puts it together and Stu comes to his house to see it. In his only appearance, he wears a white t-shirt and a blue jacket.
In "The Long Road Home", Buster mentions that Stu walks everywhere and is in great shape. According to Buster, Stu once tried to walk from Crown City to Elwood City, but he twisted his ankle on a tree root and couldn't finish.
Stu is seen during Buster's imagination in "Finding Family in Chennai".