A SIR Unit is an Irken built android, designed to function as a servant. Typically, SIR units are silver with red eyes, shoulders, and chestplates, with no visible mouth.
Standard-Issue Information Retrieval units are assigned only to Irken Invaders. They obey every command that they are given, and can be altered and reprogrammed at their master's or mistress' will. They can speak, despite not having mouths (with the exception of GIR).
SIR Units can be given markings to distinguish them from other SIR units, as shown with MiMi, having an Irken emblem on her forehead. They are very deadly, due to the fact that they have an assortment of weapons at their disposal and jet-boosters installed in their feet (with an undocumented fuel powering those boosters); as a result, any type of malfunction no matter how big or small can be lethal to both Irken and enemy alike.
They seem to be made out of a metal that is both highly durable and flexible (unlike any metal created on Earth), as they are able to change the shape of their eyes to form facial expressions, and GIR is able to move and manipulate his mouth to compensate for his mood swings and manic episodes. In one of the cancelled episodes (which later became a comic), GIR survives being hit by a car without gaining any injuries whatsoever.
In "The Nightmare Begins", Almighty Tallest Red stated that SIRs can also double as thermoses, but GIR is never seen turning into one. This may be because the empty space in GIR's head that is supposed to be a thermos is usually filled with random junk like beehives, cupcakes, or salted nuts.
SIRs are near-literal omnivores as GIR has been shown to consume all manner of organic matter such as pudding, tacos, and even babies. However, this ability may be unique only to GIR, as all other SIR Units don't have mouths and therefore don't have the need to eat,
SIR Unit Code
The SIR Unit Code is a law of the Irken Empire covering SIR Units and their freedom. It is only mentioned in "GIR Goes Crazy and Stuff". As explained by GIR in duty mode, the code enables a SIR Unit's free will in the event that they and their master's mission is under threat.
Known SIR Units
- Despite his "malfunctioned" status, GIR is a SIR unit with the usual weapons, except for that the fact that he has a mouth, cyan markings, and a defective brain. His name is apparently an acronym, although he himself states that he doesn't know what it means. For a long time, it was believed that because he is made of trash, that GIR's name possibly stands for "Garbage Information Retrieval", until Jhonen Vasquez said that the "G" didn't stand for anything. GIR was made of broken parts of SIR units from a trash can made by the Tallest for Invader Zim. His brain consists of lint, a paperclip, two coins, a screw and a gumball (as seen in "The Nightmare Begins"). Unlike other SIR Units, GIR's torso is not divided into two segments, suggesting that GIR's body is that of an outdated model of a SIR unit.
- MiMi is a modified SIR unit custom-made by Tak. She is distinguishable from standard SIRs by the emblem on her forehead and the large, extendable claw that replaces her right arm. She also seems to have a white chestplate and dark blue shoulders.
- Invader Skoodge's SIR (pictured) assisted with the conquest of Blorch, but was not present when Skoodge appeared before the Organic Sweep ceremony, nor in any of Skoodge's future appearances in either the produced or unproduced episodes.
- Invader Larb's unnamed SIR made its first and only appearance in "The Nightmare Begins", where it was ordered to warm up its master's ship's engines as soon as it was activated.
- Invader Flobee's SIR was seen in "Planet Jackers" alongside its master, lounging with him on the throne. Interestingly, while Flobee was wearing a horrible disguise, the SIR Unit was not.
- Invader Stink's SIR Unit was not seen once he completed his mission.
- Invader Skutch's SIR Unit was not seen during his master's decimation of his assigned planet.
- Invader Slacks's SIR unit was not seen in "Walk for Your Lives", however it's possible that he was still somewhere within the base.
- Invader Tenn's SIR was not seen as she was attacked by other malfunctioning SIR Units in "Megadoomer", suggesting it was destroyed, though we would probably have seen it in the canceled episode "Top of the Line."
SIRs (except modified SIRs, such as GIR) come in a standard look and with standard weaponry, including:
- No visible mouth
- About two feet tall; it is possible that the Irkens' choice of making their servants so small was influenced by their culture's obsession with height.
- Missile Launchers
- Assortment of Guns (such as Plasma Disk Launchers)
- Catapult Launcher
Mishaps with SIR Units
There was one situation in "Megadoomer" where Invader Tenn was attacked by malfunctioning SIR Units that were supposed to have been sent to Invader Zim, but the destinations were switched by a rebellious slave worker. It cost her the mission. Interestingly, all the malfunctioning SIR units act almost exactly like GIR.
Facts of Doom
- In "Megadoomer", the defective SIRs have voices that sound like GIR's (except they're voiced by Wally Wingert, Kevin McDonald, and others), which may imply that GIR's voice pattern is an aspect of SIR malfunction.
- Likewise, the malfunctioning SIRs are stated to have "eaten everything" possibly implying that GIR's insatiable appetite is another malfunction.
- In Issue 23, a Scientist named Hok claimed he developed the original SIR programming, and implemented a digital brain scan of himself as its error-correcting software.
- In "Walk of Doom", Zim refers to Irk as "our [him and GIR's] home planet", suggesting that the SIRs are purely Irken technology as opposed to Vortian.
- Despite being technically genderless, they are often referred to with gendered pronouns. However, it cannot be determined if they are programmed with gender.
- Given the fact that the Tallest gave the SIR Units to the Invaders, it's possible that they are property of the Irken Empire and don't belong to the Invaders themselves and if that's the case, they are most likely returned to the Empire once an Invader's mission is completed, this is hinted to be the case as in "Battle of the Planets" after Invader Skoodge conquered Blorch, his SIR Unit was nowhere to be seen, suggesting it was returned to storage to assist another Invader in the future.