Nydus Worm

The nydus worm was a zerg transport strain that posed a grave threat to areas previously thought secure. By the Second Great War it had become an evolution of the older nydus canal, a creature that lived within a nest-like structure called the nydus network and could travel from that network to any nearby location its controller could see, carving a tunnel beneath the battlefield as it went. Through these tunnels the Swarm could move its land creatures across any battlefield or landmass, emerging suddenly behind defensive lines that had thought themselves safe.

Biology and function#

By the Second Great War the nydus worm had become an evolution of the older nydus canal. The worm lived inside a nest-like structure called the nydus network and could travel from the network to any nearby location its controller had already seen, carving a tunnel beneath the battlefield as it advanced. The creature was capable of stretching itself out to prodigious lengths, supporting the tunnel it dug with its own skin and ribs. A nydus worm had no brain of its own, only a simple array of organs that reacted to peristaltic motion and to chemical stimuli relayed from the network. This array allowed the creature to navigate difficult or rough terrain and to regulate its biological functions; in truth the worm was merely an extension of the network itself.

Zerg warriors could enter the tunnel either through the worm's head or through the network, and they traveled through it at great speed thanks to a combination of peristaltic motion and chemical stimulants that directed their movements. To carry the Swarm's land creatures across any battlefield or landmass, the worm could stretch indefinitely through on-demand tissue generation, expanding and replicating its cells at a simple command to cover the distance to its target. Surplus tissue was reassimilated once the worm returned to the network. The very large, thick teeth set throughout the worm's mouth served primarily as digging tools: each fang was connected to a set of powerful muscles that vibrated at hypersonic speeds to crush soil, rock, and everything between. As friction wore a tooth down, it was ejected and a new one grew from the muscle itself within seconds. When the worm finally emerged, gigantic spikes protracted from its body to stabilize the creature and support its weight while the Swarm advanced from the depths of the network onto the target area.

The tunneling produced enormous quantities of detritus, which the worm disposed of efficiently. The crushed rock and soil was coated with a strain of corrosive creep secreted by glands around the creature's maw; once liquefied, the detritus trickled down into twin passages that carried it to a specialized layer beneath the epidermis, improving the weight distribution of the tunnels the worm supported with its skin and ribs.

Use by the Swarm#

Once the first worm tunnel had been excavated, more could be created, one at a time, and because all nydus worms and networks were directly connected to one another, the zerg could in time render an entire battlefield accessible. The strategic value of this lay in surprise and reach, allowing the Swarm to deliver forces to areas previously thought secure and to strike from beneath rather than across a defended frontier. The principal limitation was fragility: for all its size, a nydus worm was not particularly durable, and a single worm could be brought down with relative ease. A more developed strain, the greater nydus worm, was described as a powerful variant capable of tunneling across incredible distances, served by its own greater nydus network in the same fashion as the standard creature.