Dholes are a race of incredibly huge worm creatures. Little is known about these creatures, not even their planet of origin. It is likely they are related to the Bholes that dwell in the Dreamlands, in the Vale of Pnath. The Dholes are shown living on the world of Yaddith and slowly eating the planet away through tunelling.
They are highly carnivorous, and despite the magical and technological skill of the native Yaddithians, they were forced to abandon the planet to the Dholes after hundreds of years of fighting them.
It is implied that the Dholes follow the Yaddithians wherever they go, though that seems unlikely. No Dholes are known to exist on Earth, as they would surely cause the slow death of the planet.