Stheno

In Greek mythology, Stheno was the eldest of the Gorgons, a trio of sisters with serpents for hair and other deathly attributes. She was the sister of Medusa and Euryale.

Although she and Stheno could not turn living beings to stone with their gaze like her sister Medusa, Stheno and Euryale were immortal while Medusa was just mortal.