Zim

Invader Zim is the titular protagonist and anti-hero of the series by the same name

Appearance
Zim's appearance, like that of most of the Irken race, seems to be based off the typical "little green men from outer space" stereotype. Many Irkens are about the size of a preteen schoolchild, but Zim is exceptionally short. In The Nightmare Begins, Zim was shown to be even shorter than the notoriously diminutive Skoodge.

Zim also has ruby-colored eyes; a very common trait in Irkens. It was also mentioned in Walk of Doom that Zim's eyes contain ocular implants. Since the eyes he was born with are not visibly different from subsequent appearances, it can be assumed that these implants are subcutaneous. As he considers himself to still be an Invader, he continues to wear the standard uniform: a red tunic-like garment with a pink collar and sleeves, as well as black boots and gloves.

He also possesses a pair of antennae; their exact function is unknown, but they seem to function like human eyebrows; rising and lowering to convey emotion. It is possible that they also function as an organ in place of ears, as they picked up vibrations in Battle of the Planets.