Medusa

Medusa was one of three Gorgons that arrived on Earth during humanity's early history.

She was the best known of the three and was often depicted as being a beautiful woman with snakes for hair. Like all Gorgons, she was noted for having the power to turn anyone who looked at her to stone. She was killed by the Greek hero Perseus. Her companions were later killed by Professor Edgar Nelson-Stanley and Sarah Jane Smith's team, respectively. (TV: Eye of the Gorgon)

The Second Doctor and Zoe encountered Medusa in the Land of Fiction. This was a fictional construct based on the legends surrounding the real Medusa. (TV: The Mind Robber)

Logan compared the Cyrene's appearance to a Medusa. (AUDIO: Bang-Bang-a-Boom!)

A woman resembling Medusa was one of the attractions at the Ancient Worlds theme park on Dewyn. She came under the control of a Chiffala and was used to attack guests attending the park. (COMIC: Minor Trouble / Inhuman Sacrifice / Crimes and Punishment)

Thorsuun's smile was one that Martin Kerbe used to read about in stories of the Medusa turning her victims to stone. (PROSE: Invasion of the Cat-People)

Alternate timeline
In Andrea Yates' World, where the Trickster manipulated events so that Sarah Jane Smith died in 1964, the Gorgons never came to Earth. As the Trickster explained to Sarah Jane while she was in limbo, he had turned away all the foes she would have defeated, his intention being for her absence to allow Earth to be destroyed by the meteorite K67. (TV: Whatever Happened to Sarah Jane?)

Behind the scenes
Medusa was played by Jemima Rooper in the BBC series Atlantis.