Voracious Craw
The Voracious Craw featured in the novel Sick Building is a member of a species of the same name.
An adult Voracious Craw somewhat resembles a gigantic tapeworm or other mollusc, large enough to be seen from space when cruisisng just above a planet's surface. As the name implies, the Craws are seemingly permanently hungry, and will eat everything that they can, animal, mineral or vegetable. How a Craw actually eats has not yet been made clear. Anything below the mouth of a Craw is pulped and sucked up into the mouth itself, but as the Craw does not actually touch the food, how this occurs is a matter of some debate. The cover of the novel Sick Building shows the Voracious Craw to have teeth, but this is not so.
Although the Craws are a species without technology, the presence of a Craw nearby sends most technology haywire, and the Craws are somehow able to cross vast distances of space without suffering any ill effects.
When a Craw arrives at a planet, the first thing that it does is check to see if another Craw has got there first. If one has not, that Craw then proceeds to devour everything on the planet that it physically can. If it meets another Craw, the larger one is allowed to feed on the planet and the smaller must leave. The sound of a larger Voracious Craw can be modelled by playing back and distorting human burps, and this technique was used to great effect to save the inhabitants of Tiermann's World.