Disguises are a vital tool required by Irken Invaders so that their true identities are not exposed to the inhabitants of the planet they are assigned to conquer. They are each given a special piece of cutting-edge technology from which they can choose a disguise based on what the inhabitants of their assigned planet consider "normal". However, almost all Irkens choose awful disguises, despite having a handful of excellent options to choose from. Like their Irken masters, SIR Units also require disguises; most creatures would become suspicious if they caught sight of Irken technology on their planet, since most beings in the Invader Zim universe are, consequently, aware of the Irken race's mission of galactic conquest.