Alvega Earthworm

The Alvega Earthworm was a massive earthworm which existed on the planet Alvega.

History
A worm was used during the battle for Alvega when the Controller ordered the worm to attack the three Dalek ships that were on the ground at the time.

A fourth ship that had tunneled to the core of Alvega encountered the worm but it was eventually killed by the Daleks. (TV21: The Amaryll Challenge)