1) There is only one Medusa, and although, in some traditions, it was originally a beautiful being, it became a vicious monster. And she was eventually beheaded. So I would rather choose the mermaid. 2) "In Greek mythology, Medusa (Greek: Μέδουσα (Médousa), "guardian, protectress, queen". Her name probably derived from the feminine present participle of medein, "to protect, rule over".), a sea nymph, was one of three gorgon sisters, and the most beautiful. She was courted by Poseidon, and made love to him in a temple of Athena. Furious, Athena transformed Medusa into a monstrous chthonic beast with snakes instead of hair, whose frightening face could turn onlookers to stone. She was beheaded by the hero Perseus, who thereafter used her head as a weapon until giving it to the goddess Athena to place on her shield. Having coupled with Poseidon previously, two beings sprang from her body when she was beheaded. One, Pegasus, was a winged horse later tamed by Bellerophon to help him kill the chimera. The other, Chrysaor of the Golden Sword, remains relatively unknown today." Source and further information: http://en.wikipedia.org/wiki/Medusa 3) I would not either choose a gorgon: "In Greek mythology, the Gorgon (plural: Gorgons) (Greek: ΓοργÏŽν or ΓοργÏŽ Gorgon/Gorgo, "terrible" or, according to some, "loud-roaring") was a vicious female monster with sharp fangs who was a protective deity from early religious concepts. Her power was so strong that one attempting to look upon her would be turned to stone, therefore, such images were put upon items from temples to wine kraters for protection. The Gorgon wore a belt of serpents that intertwined as a clasp, confronting each other. In late mythology, it was said that there were three Gorgons and that one of them, Medusa, had hair of living, venomous snakes that she received as a punishment from Athene and that image has become especially famous. However, the Gorgon exists in the earliest of written records of Ancient Greek religious beliefs such as those of Homer." Source and further information: http://en.wikipedia.org/wiki/Gorgon 4) Although many mermaid tales describe them as provoking some kind of disaster, they are also mostly described as very beautiful. The "mermaid problem" would also have to be considered... "The Mermaid problem is an observation occasionally mentioned in literature, concerning the difficulty of having sexual intercourse with a mermaid. Although mermaids are commonly depicted as beautiful, variably nude, and enticing, a man attempting hypothetical sex with one would be thwarted by the typical portrayal of the creature: a fish from the waist down, with no vagina. Some fiction, aware of the long running question, deliberately avoids the question for humorous effect. More generally, it can also be a joking reference to the unusual sexual interest many non-human characters seem to have with humans in fantasy or science fiction, and potential physical issues therein." Source and further information: http://en.wikipedia.org/wiki/Mermaid_Problem Further information: http://en.wikipedia.org/wiki/Mermaid