He is quite small and easily recognizable due to the red police light atop his body. GO-4 is equipped with two salute-ready arms and an anti-gravity stasis beam. For communication, he had various beeps and other sounds. GO-4 units also can deliver coffee to superiors.
WALL-E
GO-4 serves aboard the Axiom as the Captain B. McCrea's first mate, and helped Auto in his attempt to carry out Directive A-113. He was accidentally destroyed when he attempted to assist AUTO in taking down Captain B. McCrea and was kicked and sent flying through a window and crashing down near one of the swimming pools in the Lido Deck.
GO-4 used his personal elevator system to move fast around the Axiom. The entrances/exits of the elevator were usually at Steward Kiosks, the places where SECUR-T (Steward bots) were waiting inactive until they were needed. The elevator also granted GO-4 an access to the captain's quarter.
One also appears in the video game, but it does not get destroyed.
Trivia
GO-4 is a pun on how personal assistants are often referred to as "gophers," a verbal pun as they are often sent to "Go for (GO-4) things."
When GO-4 is sent flying out of the window, he makes a whistling sound and a smash sound very similar to the sound Wile E. Coyote makes when falling off a cliff in Looney Tunes.
Gallery
Attempting to destroy the plant by putting it in the escape pod