medusa (mythology)

One of the gorgons of Greek mythology, and the only one who could be killed. Such was her hideousness that anyone that looked directly at her was turned to stone.
She was beheaded by the Greek hero Perseus and her blood, splattered during the beheading, gave birth to Pegasus and Chrysaor.

Usually portrayed with snake hair (but that does not mean all instances of snake hair portray her). On occasion drawn with the lower body of a lamia or with other snake-like traits.

Stories that draw on the myth often "invert" her power: instead of you seeing her causing petrification—which, among other things, implies it is involuntary on her part—it's her seeing you. Her petrification effect is then connected to her eyes rather than her overall appearance. This gives visual works license to make her attractive.