As a mythical Gorgon, Meduson has the power to immediately turn anything that looks directly at her to solid stone. Some Psymonsters might think of this as a curse, but she loves it, even if the effect does only last a few hours. Unfortunately for her naughty and troublesome hobby, her legend becomes so popular and illustrious that almost none of the Psymonsters fall into Meduson's trap these days. She tries all kinds of tricks, like hiding behind bushes and suddenly jumping out, pretending to be inside a television set, and going undercover in the reptile house in the Psymonster World, but the hissing of her hair always gives her away.
She is a lime Gorgon with red eyes, teal lips, sharp fangs, a green bra and a loincloth, a dark olive mouth with an olive tongue, and six green snakes as her hair.
- Her name is a combination of "Medusa" and "poison".
- Meduson is one of the three Psymonsters who wear loincloths (the other two are Sinclops and Quarrelous.