Viruxes are nanological infections that have been designed, modified and often re-vised or hacked over time until they have acquired all sorts of strange, exotic and often dangerous quirks, capabilities or effects. Especially the non-domesticated forms that travel around as free-floating infections of opportunity in some of the less hospitable regions and questionable biomes of wrecked worlds or collapsed closed-ecologies where entire clades have fallen to some mutated nanopathogen that once served them or protected them from the horrors of the worlds outside their arcology-fortresses.
You can learn more about them at the Riskail Blog where this post has been transferred. You can find it here.