Voracious Craw

Voracious Craw were giant worm-like creatures which could lay waste to planets by devouring everything in their paths.

Biology
Craws resembled tapeworms. They were green-grey in colour, and had few features except for a ring of eyes around their colossal mouths. They grew to huge sizes, looking like continents when viewed from space. Craws were always hungry, and would eat anything, be it animal, mineral or vegetable. Voracious Craws had no teeth, and did not need to chew their food. Anything below the mouth of a Craw was pulped and channelled into the mouth itself.

The presence of a Craw created an electronic disturbance, which sent nearby technology haywire. This disturbance was so powerful that it could even hinder the operation of the Tenth Doctor's TARDIS.

When a Craw arrived at a planet, the first thing that it did was check to see if another Craw had arrived there first. If one had not, the Craw would begin devouring everything it came across. If two Craws met on the same planet, the larger one would feed and the smaller one would depart. (PROSE: Sick Building)

History
A Craw once began devouring Tiermann's World. It was headed for the Tiermann family home, the only settlement on the planet. The Tenth Doctor, Martha Jones and Solin Tiermann eventually used the amplified sound of their burps to mimic a larger Craw, scaring the Craw away. (PROSE: Sick Building)

Behind the scenes

 * The cover of Sick Building shows the Craw with teeth, but this is not so.
 * Voracious means "ravenous" or "greedy".

Voracious Craw