SIRNS resembles an ordinary SIR unit, apart from the fact he has a mouth, bright lime green glowing parts as opposed to red, and also has unique arms with three talon-like claws, and no antennae. He is also slightly darker than most SIR units.
SIRNS is usually hyperactive, constantly screaming these words: "Can we go to Space Pastry? HUH?!? Doughnuts! Wanna get doughnuts! From Space Pastry!", clearly hinting he's obsessed with doughnuts. He also has an unusual obsession with smiley faces, owning a collection of smiley face bouncy balls, smiley face pencils, even smiley face underpants. He is prone to distraction and if you're trying to get his attention by simply saying his name while he's watching Irk's Funniest Home Videos, you're wasting time.
- Arsenal - Like a typical SIR unit, SIRNS has an arsenal of weapons. He has a unique arsenal though, consisting of grenade launchers, laser blasters, plasma cannons, catapults, missile launchers, razor disc flingers, machine guns, and SIRNS' favorite, the chainsaw.
- Claws - SIRNS can use his sharp talon-like fingers as deadly weapons, to great effect. Ize occassionally uses SIRNS as a paper shredder.
- Rocket Pack - SIRNS has a unique retractible jet pack that allows him to jet across space, occassionally breaking the sound barrier.
- SIRNS, along with Invader Ize, were created as characters on the 2008 computer game Spore by user Invader_ZIM_Fan.
- SIRNS was built out of trash from a dumpster by Tallest Purple, with a bolt and a spring from a pen for a brain. This explains a lot.