Garxxax is a small world on the fringes of Terran Dominion space. It has a tropical climate with mountainous rainforests, and high humidity. Heavy rainstorms are common through the planet. Unnaturally warm oceans cover the majority of the planet's surface.
Garxxax is the homeworld of the zantar slug, the evolutionary predecessor to the roach. It has a extremely powerful slime that can eat through neosteel, and powerful regenerative capabilities. Another common lifeform is a vine that can attach to neosteel and form a powerful bond, but has an extremely flammable sap. When the zantar slug's acidic excretions and this sap combine, the result is an extremely powerful explosion.
The Dominion held a research station on this world to study the native lifeforms there, manned by ten scientists and First Security Officer Lee Treicher (named Illyana Jorres at the time). A wounded zerg behemoth landed on the planet, and attacked the habitation stations in order to obtain biomass. When the zerg found the zantar slugs on the planet, they assimilated it into a new strain, the roach. The base was evacuated, but the instillation was lost to the zerg.