Anima exterminatore (Racuna in Buyukspeak) is a nanobot artificially created during the Buyuk Civil War as a weapon against the Anti-Machines.
The Racuna virus only affects Ghorax as well as those with Ghorax implants. Non-Ghorax can normally fight it off with an adequate immune system, so to contract the virus, they have to be implanted directly.
The virus attacks by programming the production of nonfunctional cells that replicate uncontrollably. It does this by directly attaching itself to the cell's DNA to rewrite it.
Deliberately, the virus was designed to be only countered with Buyuk-origin cybernetic implants. The virus is directly integrated with these implants and will slow down the cancerous cells to a halt, eventually getting rid of them. However, if the implants are ever removed, or if someone attempts to tamper with them, the virus is programmed to cause a self destruct, breaking down the body into raw proteins and frying the circuitry of the implants. This serves as a defensive measure against finding a cure.
Although done deliberately to ensure population control, one of the major drawbacks is that the Racuna sterilizes the victim. Therefore, the only way implanted Ghorax can reproduce is to implant other Ghorax or other aliens.