Space pants originated on the planet SLKSSKZ, where they lived symbiotically with the local creatures. Eventually, the planet was decimated and the creatures were driven to extinction. The space pants now travel from planet to planet in an attempt to find new hosts to attach their legs to.
Zim allies with the space pants' queen, the Ubertrouser, using the space pants to conquer Earth by having them take all the humans as hosts. However, Zim was planning to betray and destroy the space pants once they'd disposed of all the humans for him, allowing him to take the Earth for himself. When Dib exposed this scheme, the Ubertrouser turned on Zim, causing him to destroy all the space pants prematurely.
Space pants have strong telepathic abilities, able to take over the mind of anybody they attach themselves to. The pants spread by making the wearers of the pants force other people wear the pants. After about a year, the pants eat the legs of their wearers.
Space pants are hatched from pants eggs, and pants eggs are laid by the pants queen known as the Ubertrouser. Ubertrouser, in addition to showing telepathic abilities, is also capable of generating bursts of psychic energy (manifested as red beams of light). She also has knowledge of ancient pants-based-martial-arts.
- Zim also mentions "space pants" in the first and seventh issues as well. However, the context there would imply that he's referring to actual articles of clothing, and not the species.
- The means of the space pants' reproduction - a queen laying eggs that hatch parasites which latch onto hosts - is quite similar to that of the Xenomorphs from the Alien film franchise.
- It's unclear if the space pants that appear on Earth are just one group of them, or the entire species.
|Species of Invader Zim|
|Brain-Eating Parasite • Hogulus • Humans • Irkens • Large-Nostril People • Martian • Meekrob • Nhar-Gh'ok • Plookesian • Rock Species • Screwheads • Slaughtering Rat People|