Created around 3628 BBY by Darth Malora, the mutant Geonosians were made from several species—Geonosians, Acklays, Killiks and Melitto— in a combination of genetic engineering and Sith alchemy. The original Geonosians in the experiment were bought from a secretive group of Hutt gluttons as adult slaves or in egg or larva forms.
The insectoids were developed to be self-sustaining warriors and hard to eradicate with thick armored carapaces, rapid reproduction, and heightened sensory capabilities. The mutated Geonosians gained in strength but were removed of most of their sentience, with just enough to operate light weaponry such as blasters and vibroblades.
The Mutated Geonosians were deployed by Darth Malora during the Invasion of Ossus against the Jedi Order's colony but eventually they turned rogue attacking the Sith Empire's forces as well as the Jedi and those of Republic reinforcements.
The Mutated Geonosians established their nest in the mountains, under the rule of the Mutated Geonosian queen.