Gorgon (mythology)

From TARDIS Index File, the free Doctor Who reference.

The Gorgon was a hideous creature possessing snakes for hair and the ability to turn whoever looked upon it into stone. Orginally from Earth, it came to Zeno and began turning the inhabitants to stone. When the Doctor, John and Gillian arrived on Zeno, they saw all the statues and realized what had happened to the people. They put on blindfolds and used Gillian's mirror to show the Gorgon its reflection, turning it to stone. (TVC: The Gaze of the Gorgon)

The Gorgon in this story seems to be of a different species than the Gorgons encountered by Sarah Jane Smith.