The Abbess (Eye of the Gorgon)

The Abbess was originally a Human, who, now possessed by Gorgons, served as their host on Earth. Hundreds of years old, she wanted to bring the rest of the Gorgons to earth using a portal which resembled a well. She was turned to stone when Sarah Jane Smith used a mirror to reflect the Gorgon's power back on itself. (SJA: Eye of the Gorgon)