Rock Creature

Ogron eaters were large, orange, blobby creatures native to the Ogrons' home world. They preyed upon Ogrons, yet were worshiped by them fervently. The Ogrons were said to fear these "monsters" even more than they feared the Daleks.

During a human-Draconian expedition to the planet, the Third Doctor saw one of the creatures eat one of the Ogrons that were attacking them, causing the other Ogrons to run away. The Doctor would later use the Master's hypnotic device to take the image of the Ogron eater and frighten off the Ogron guards. (DW: Frontier in Space)

In the novelization of this episode, the Ogron Eater is a giant lizard that is said to bear a resemblance to a Tyrannosaurus rex.