Medusa, Medusa Gorgon, Mrs. Gorgon or Maddy is the mother of Deuce Gorgon. She is a powerful gorgon, and in old mythology, Perseus had slayed her. In the form of Monster High, she just encountered this warrior but he failed. This the joke for Deuce's pet's namesake, Perseus. Medusa is a strong gorgon, who, in the books, is only referred to as Maddy, not revealing her true identity, to attract two much attention. She's powerful, and has a good strong mind to scold Deuce when needed.
In other parts of the franchise, she attends to be a nag as heard from in "Fright On!". Though she is a good-natured woman, perhaps, she can tend to make her son Deuce uncomfortable and feel the need to "break up on her" with his snake hair snakes as seen in "Fright On!", pretending the phone line is breaking up. In the Monster High books, she goes by the nickname Maddy Gorgon.
- Medusa is the sister of Stheno, and also the sister of Euryale, other two gorgons, who, together, with Medusa, are known as the "Gorgon Sisters", the youngest gorgons.
- Like her son, she wears sunglasses to prevent from people to turning into stone with her glare.
- She is one of the parents at the R.I.P (RAD Intel Party), a Regular Attribute Dodger intel party in Monster High.
- In The Ghoul Next Door her first grey hair, became Cleo's pet Hissette.
- Viperine Gorgon is her niece.