Alvega Earthworm

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

It is unknown if more than one worm existed, but one 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)