Medusa was a daughter of Phorcys and Keto, and was once a priestess of Athena. Poseidon was bitter at Athena for recently turning his beloved Coronis into a raven, and beating him to the city of Athens, so he decided to get back at her by seducing Medusa within the goddess' virgin temple. As a result, the infuriated and disgusted Athena cursed Medusa and her sisters, much to Poseidon's horror and dismay. The girl's hair was turned into serpents and anyone who would look upon her gaze would turn to stone. Her sisters, Stheno and Euryale, were eventually made immortal, though they do not have the power to turn people to stone like their sister.
Medusa had two children with Poseidon, Chrysaor, who was born from her neck, and another child, Pegasus, who was born from her blood when Perseus beheaded her (while the Gorgon was asleep). The hero would subsequently use Medusa's severed head to defeat Poseidon's ferocious sea serpent, saving Andromeda in the process.
Posing as an old Middle Eastern lady named Aunty Em, Medusa lures people into her "Emporium" and then turns them into statues by making them look at her face, usually directly at her eyes. She wears a veil to hide her face. She pretends to take a photo of her victims and lifts the veil to uncover her head, thus turning her victims to stone. Medusa turned many people and creatures into statues, including Grover's Uncle Ferdinand.
At one point, Percy Jackson, Annabeth Chase, and Grover Underwood are lured into the shop by the smell of food during their Quest. Grover notices that a statue in the shop looks like his uncle. Medusa feigns kindness, by giving them food and talking to them about her shop. She also mentions that her sisters are gone. (They faded because people forgot about them.). She then tries to get them to pose for a photograph and turn them into statues.
Grover realizes that the suspicious statue is indeed his uncle. Annabeth and Grover realize who Aunty Em really is. They try to convince Percy that they should leave. Percy, however falls for Medusa's kind words and refuses. A few minutes later, Percy realizes that "Em" means "M" for Medusa.
At this point, Medusa reveals herself. It becomes too late to escape, so the trio decide to fight Medusa. After a brief struggle, Percy defeats Medusa by severing her head with Riptide, his celestial bronze sword, using a polished bronze ball as a mirror. He then sends the head to Olympus via the Hermes Express.
Later in the book, Percy gives Medusa's severed head to his mother, Sally Jackson. She uses the head to turn Gabe Ugliano, Percy's abusive stepfather, and his friends, to stone. Sally goes on to sell the stone statues as a work of art. She uses this money to pay off her debts and get a better life for her son and for herself.
Medusa does not formally appear in this book. However, Kronos uses her lair as his base in the Battle of the Manhattan. While speaking to Ethan Nakamura, Kronos mentions that unfortunately for him, Medusa has not reformed since Percy had defeated her four years ago.
May Castellan is also shown to have a TY Beanie doll of her that she calls "Mrs. Medusa."
Medusa's sisters, Stheno and Euryale, try to chase down and kill Percy Jackson, the last person to kill Medusa. One Gorgon even looks like her sister, Medusa. She is shown to be scared she would turn to stone by seeing her own reflection. The two become mad at Percy for believing that they can turn him to stone like their sister.
Medusa is actually kind to Percy in The Lightning Thief in her own strange way. She wants him to stay with her forever by becoming a statue. Annabeth reveals that Medusa and Poseidon were former lovers (also mentioned in Percy Jackson's Greek Gods). Since Percy is Poseidon's son, Medusa does not want him to suffer. Yet, when Percy and his friends decide to fight her, she attacks him and gets killed in the process.
On the other hand, Medusa harbors a strong hatred against the family of Athena. Athena turned her into the fearsome monster she is. Medusa wants to turn Annabeth into a statue and destroy her, because she is a daughter of Athena. This way, she hopes to take revenge on Athena. However, she is unable to do so.
As seen in Percy Jackson's Greek Gods, Medusa used to be a beautiful woman. After Athena cursed her, however, Medusa was transformed into a tall woman with slithering green vipers for hair (which gave off a nauseating "reptilian smell"), long hands with sharp brass talons, and bat-shaped wings of Imperial Gold.
According to Percy Jackson's Greek Heroes, when Perseus encountered Medusa, she wore a simple white chiton. Her belly was swollen, as she was pregnant with Pegasus and Chrysaor. Her face had tusks like a wild boar's jutting from her mouth, Her lips were curled in a permanent sneer. Her eyes bulged, making her look vaguely amphibian. According to Perseus, her features were misshapen and disproportionate and made her look very grotesque. Hence, a reflection of Medusa's face was akin to an optical-illusion picture that makes observers dizzy and nauseous when stared at for too long, only "a thousand times worse." When she briefly awakened, Medusa shrieked "like an electrocuted jackal" while lunging at Perseus.
In The Lightning Thief, she wears a long black gown, and her face is a shimmering pale circle under her black veil. In disguise, her body looks normal, but once she takes the disguise off, she reveals she has green snakes instead of hair. She speaks in an exotic Middle Eastern accent, which her son Chrysaor is seen to have inherited.
- Gorgon Petrification: If someone looks into Medusa's eyes, they turn to stone. She is said to be petrify people due to her uglyness.
- Post-Mortem Petrification: Her head can still be used to petrify people after it has been removed from her body.
- Snake Hair: She can use the snakes in her hair as an offensive weapon.
- Talons: Her hands turn into sharp claws that can tear through flesh.
- Charmspeak: She has an extremely persuasive voice; she could slightly charmspeak.
- Gorgon Blood Properties: As is the case with all Gorgons, blood from her right side can cure anything, but the blood from her left side is deadly, as it killed Phineas even when the Doors of Death were open and under Gaea's control.
As the child of two ocean dieties, it can be inferred that she may have or have had other powers.
Known Victims of Medusa
- Ferdinand - He was enticed into Medusa's lair during his quest to find Pan.
- Gabe Ugliano- After her head was cut off.
- Hydra- In The Lightning Thief (film), Grover Underwood used the head of Medusa to turn the Hydra to stone at the Parthenon in Nashville.
- Unknown woman and her husband - In The Lightning Thief (film), a woman was with Annabeth Chase when they first encountered Medusa. She opened her eyes and was turned to stone while holding Annabeth's hand. She also claimed that her husband was turned into stone before her.
- In both the film and book versions of The Lightning Thief, Medusa's lair is filled with statues of people that had been turned to stone by Medusa. In the book, one of them is a girl holding an Easter egg basket.
|from the official soundtrack|
- As revealed in Percy Jackson's Greek Gods, the actual reason that Poseidon took Medusa into Athena's temple was to get back at the goddess for turning Coronis (a girl whom Poseidon had tried to seduce) into a raven.
- In mythology, Medusa was said to be the only mortal sister of the Gorgons, but in the series she is treated as a monster.
- Some depictions of Medusa describe her as half woman and half serpent, with her hair being a mass of poisonous snakes and having a long serpent's tail as the lower part of her body.
- In the film, when Medusa is turning someone to stone her eyes glow a silver white color and her snakes hiss in unison at the victim.
- According to The Son of Neptune, Medusa's mother says she is the most hideous one in the family, of the three Gorgons.
- Medusa and her sister Stheno both have green snakes for hair while Euryale has coral snakes.
- A group of living organisms belonging to the Cnidarian family are named Medusa, since they have tentacles hanging like the snakes in Medusa's hair.
- Blind people, as well as immortals are immune to her curse.
- The origin of Medusa in which she was cursed by Athena comes from Metamorphoses, written by the Roman poet Ovid.