Snakypoo was the magical shampoo that Athena made, although it was all wasted on Medusa, as Medusa believed that it would make her hair shiny and everyone would have to notice her, since that was when Medusa did not transform into a gorgon monster.
Snakypoo was thought, even by Athena, to make one's hair shinier and noticeable. Medusa, envious of the prettier goddessgirls in the school, steals it and applies it on herself. She soon gets strange powers such as turning mortals into stone, with Pandora's "statue" out in the courtyard, which drove everyone suspicious.
The next day, Medusa completely transformed into a monster, making her even more unattractive. This magic cannot be undone, even by Athena.