Medusa is a fictional character in the Marvel Comics' universe. Her real name is Medusalith Amaquelin. She belongs to the race of Inhumans, a species of prehistoric earthlings mutated by the Terrigen mists produced deep under the Inhuman city-state of Attilan, presently located in the oxygen-rich Blue Area of the moon. Medusa is married to Black Bolt and they have a son named Ahura. Crystal, the wife of the Avengers Quicksilver, is Medusa's sister.

Medusa first appeared in Fantastic Four #36, making her one of the oldest characters in the Marvel Comics' universe. At that time, she suffered from amnesia and affiliated herself with the Frightful Four, Silver Age nemeses of the Fantastic Four. After regaining her senses, Medusa returned to Attilan and later still she joined the Fantastic Four as a temporary member filling in for Susan Richards, aka Invisible Girl, who was on leave rearing her son Franklin Richards.

Medusa appeared in the Ultimate Marvel Universe during the Ultimate Fantastic Four issue, Annual 1: Inhuman. This version had a head full of snakes like the mythical creature she is named after. She was still Black Bolt's wife and appeared to share the same relationship to the other Inhumans with her regular counter-part.

Medusa possesses a head of thick red hair that's six feet long. Her mutation gives her psychokinetic control over every strand, each of which possesses greater tensile strength, modus of elasticity and shear resistance than an iron wire of the same thickness. In combat, Medusa uses her hair to wield weapons, bind her foes, etc.

http://en.wikipedia.org/wiki/Medusa_%28comics%29