Medusa

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

She was the better known of the three and was often depicted as being a beautiful women with snakes for hair, though this was dramatized. Like all Gorgons, she was noted for having the power to turn anyone who looked at her to stone. In a challenge, 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. (SJA: 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 surrouding the real Medusa. (DW: The Mind Robber)