Doctor Chu is an elderly mouse with gray fur, visible forehead wrinkles, a white mustache, and glasses. He typically wears a white lab coat over a blue shirt and a green-and-yellow striped tie, reflecting his role as Cube Town's primary inventor.

He is grandfather to Chewy, best friend of Pecola, and maintains a close friendship with Pecola's grandfather, Pecolius. His laboratory houses numerous inventions, including a submarine and the airplane Mad Mouse resting atop it. While his gadgets frequently aid Pecola and Chewy during adventures, they often malfunction or cause unintended consequences.

Personality-wise, Doctor Chu exhibits anxiety about potential pranks and possesses a self-proclaimed "genius" attitude toward his work. He collects comic books, an interest he considers somewhat embarrassing, and demonstrates concern for others. He acts as a father figure to Pecola despite the penguin's chaotic tendencies.

Notable inventions include "Robo-Pecola," a robot duplicate intended to teach manners whose technical glitches often create greater chaos than the original. Other creations are "Tornado in a Can" for generating wind and experimental cube-shaped fireworks. These gadgets frequently become central to episodic plots when they malfunction or are misused.

The character appears across multiple franchise media: the main animated series, where inventions like Robo-Pecola hijacking Mayor Papazoni's helicopter or dismantling Steamer's train drive storylines; and printed media including the books "Golagola," "Bot and Switch," "Power Pecola," and "Paper Pecola," plus official LINE stickers. His role remains consistent as a supportive but occasionally exasperated inventor whose creations facilitate both solutions and comedic complications in Cube Town.