Nydus Tunnel

Nydus tunnels are the result of the movement of nydus worms underground. The tunnels are actually more massive than the worm itself, thus allowing for multiple types of infestation to grow on the walls. Metamorphs sometimes spawn in these tunnels, laying multiple eggs and popping them early if necessary. Most nydus tunnels are filled with legions of infested terrans and infested mobs, though some pure zerg breeds can spawn.

In areas where multiple eggs have been laid by queens or metamorphs, hundreds or even thousands of feederlings will spawn. Unlike normal zerg creatures, which will attack a mob on contact, feederlings will often flee in terror.