- “They're bureaucrats Morty, I don't respect them”
- —-Said by Rick to Morty.
The history of the species is largely unknown, but they appear to have established or otherwise obtained control of the Galactic Federation at some point. Gromflomites are shown to comprise the entire upper echelon of the Galactic Federal government, as well as most of their military, the latter referred to as the Galactic Militia. At least one Gromflomite, Krombopulos Michael, has taken on jobs that sometimes require action against the Federation, including the killing of Federation-aligned Gromflomite guards, suggesting that the species as a whole may not be loyal to the Federation. The majority of Gromflomites depicted on the show happen to be soldiers, but they are otherwise not implied to be a wholly militaristic society, with civilian Gromflomites making some appearances.
The Gromflomites are insectoid creatures, sporting many features similar to common flies and praying mantises. Their bodies are a dull green color, darker in some places and lighter in others. Their midsections are conical in shape, being larger around the head and smaller around the legs, with hunched backs. The Gromflomites' heads are typically much smaller than their upper bodies, with no visible neck. They all have large, red compound-eyes and two small antennae sticking out the top. Their mouths consist of sagging vertical lips guarded by a pair of pincers. The color of their blood is dark blue.
Most Gromflomites have two larger, pointed antennae sticking out of their shoulders; these antennae have yet to serve any real purpose and may be vestigal. They have two thin arms which get thicker and gain edges starting at the elbows, and two clawed hands that can be used for gripping. Their backs have two clear, round wings which can be used for flight. There are four udder-like appendages sticking out of their chests and two more from their groins. We know that at least the groin ones serves as shell glands or gonads.  They are capable of asexual reproduction . The Gromflomites' legs are also thin, shaped like lightning bolts, with each ending in a foot with two large claws in front and a much shorter one sticking out of the ankle.
Some Gromflomites, like Krombopulos Michael and Cornvelious Daniel, have a different design. This variation is not hunch-backed, and their jaws have larger lips and lack pincers. These Gromflomites are often seen wearing clothing or armor, unlike their more commonly-seen variants, which are usually wearing nothing. The reason for these variations are that these Gromflomites are of a higher rank, perhaps commanders, due to their armor and participation during more extreme tasks, such as arresting a prisoner, or retrieving hostages. When aroused, Gromflomites lips turn pincer-like, and pincers start arising from their body. They also secrete a special kind of grease from their elbows that is capable of getting rid of tough stains on clothing.
- The name "Gromflomite" bears some similarity to the binomial name for the Madagascar Hissing Cockroach, Gromphadorhina portentosa.
- They share some similarities with the Irkens from the animated series Invader Zim. Both are imperialistic, insectoid races capable of interstellar travel.