GIR is a malfunctioning and dimwitted robot SIR (Standard-issue Information Retrieval) Unit who was assigned to Zim. He was built by The Almighty Tallest out of SIR unit remains from a trashcan and rubbish they found in their pockets. GIR was passed off to Zim as a "top-secret" and "advanced model". His name is an unexplained, self-applied moniker. He disguises himself in public by wearing a green dog suit which fools most humans, despite looking and acting nothing like an Earth dog. Out of the pair GIR is the one who has more interaction with Earth's social and cultural life-style. This is because his personality is much friendlier and is much more easy-going. GIR also has a love for Earth that his master does not share. Throughout the series GIR has also demonstrated some talents like cooking and dancing.
GIR has no sense of who is a friend and who is an enemy. He also rarely understands the severity of the predicaments he finds himself in, unless it involves pain or very severe danger. However, to his credit he often understands it more than his master and has on rare occasion predicted the correct out-come of a very dangerous situation.
GIR's upbeat, clueless, thoughtful and friendly personality is a contrast to Zim's self-centered, imperious behavior. GIR enjoys taking part in Earth's culture, while Zim distances himself from it in order to complete his mission. GIR does not usually obey Zim, which leads to Zim furiously shouting at GIR. However, GIR and Zim occasionally seem to care for one another. Zim often calls GIR a "horrible little robot" and has referred to GIR as insane, though Zim will occasionally show some affection. He also watches classic cartoons on TVs in Zim's base and house. GIR's personality is however, flipped in the episode "GIR Goes Crazy And Stuff" after Zim incredibly increases GIR's Behavioral Modifier to a very high level. At first GIR obeys Zim without trouble or question, but as the episode rolls along the much more dangerous, cold, well-focused, rebellious, darker and serious side of GIR is shown. He also shows a very powerful thirst for knowledge about the entire planet, so it can be invaded or destroyed by Earth's much more worthier opponents. GIR furthermore comes to view his master as an idiot who is incapable to do his duties and one that uses him very poorly. GIR's new personality combined with Zim's idiocy and misuse lead into GIR hating him. However, by the end Zim puts GIR back to normal and GIR is his old-self once again.
- GIR was released as a Pop! in select Hot Topic stores in 2012.