Garxxax Base was a Terran Dominion research station on the planet Garxxax, that studied the lifeforms and climate of the planet. It had a staff of ten scientists, and one security chief Illyana Jorres.
The base used eleven biospheres to study contained specimens. Two species of note was a vine whose sap could attack itself to neosteel like glue, but was highly combustible. The second was the zantar slug, a small creature with an acid that could eat through neosteel, and extreme regenerative properties. However, the slug's acid mixed with the vine's sap produced a large explosion, so precautions had to be taken.
In 2501, a zerg behemoth, wounded by a battle with the protoss, landed on the planet. The force of the landing caused a breach in one of the biospheres, which lead to zantar slugs landing on the scientist Raynolds, killing him. The zerg moved on the biospheres in search of biomass, but found the slugs. Sarah Kerrigan saw potential in the slugs, and started the process of assimilating them into the swarm.
Illyana Jorres went to investigate the breached biosphere, and in the process had zantar slugs land on her arm. The acid ate away at her suit and caused her arm to be useless. She then found the zerg mutating one of the slugs, which she then killed. Jorres warned the scientists about zerg on the planet, but by the time they got the message the zerg had found them, killing the lot of them.
Jorres fought off the zerg, and held out just long enough for First Lieutenant Brachyan Treicher to arrive in the puddlejumper, giving her a chance to evacuate the planet. The facility was lost to the zerg, and the zanatar slugs studied within became the genetic basis for the roach.