The Wirrn are a race of insectoid creatures from the Andromeda galaxy. Although they spend their lives in space and have no need of oxygen in their pupal and adult forms, to breed they require a planet or other suitable environment with hosts. The Wirrn breeding grounds in Andromeda were populated by animals like cattle into which the Wirrn laid their eggs, but when these planets were destroyed by the human settlers who came to the galaxy, the Wirrn were forced to find new planets.
When the Wirrn eggs hatch, the larvae eat their way through the host and, if it is intelligent, acquire its knowledge. The larvae are green, with a large mouth and a pink underbelly. They secrete a kind of slime, and if a human or other lifeform touches it, they turn into a Wirrn, advancing rapidly through the larval phase directly to adult, without passing through the pupal phase. In this method, the Wirrn can rapidly convert other lifeforms without the need to lay eggs.
The Wirrn larvae are the most susceptible to being hurt by energy weapons. Once they become adults, energy weapons do not harm them. Practically the only thing that can is electricity.
Wirrn are about six feet tall with two long antennae, large spherical eyes, a pair of mandibles surmounted by a pointed horn, six tentacle-like legs sprouting from behind an armoured plate, and a segmented body ending in a large claw.
