Maryann is a minor antagonist from The Fairly OddParents!, and the main antagonist of the episode "Hassle in the Castle". She is a former godchild of Cosmo Cosma and Wanda Fairywinkle-Cosma.
She was voiced by Grey Griffin, who also voiced other characters in the series, including Vicky, along with Azula in Avatar: The Last Airbender, Asajj Ventress in Star Wars: Clone Wars, and the High Priestess in Samurai Jack.
According to Wanda, Maryann had abused their magical powers. On June 28, 1914, she wished that Franz Ferdinand (the Archduke of the Austro-Hungarian Empire) and his wife, Sophie, would be assassinated, thus plunging the world into the first World War. It was for this reason that Cosmo and Wanda were taken away from her.
It's unknown how she was able to wish that the Archduke would be killed, because in Da Rules, it states that a godchild cannot wish someone dead. Although it was possible that this rule was created because of her, or she found some sort of loophole, and most of Da Rules are created when a godchild makes a wish that negatively affects the world, such as when Timmy wished it was Christmas every day.
She was once wished out of Cosmo and Wanda's Hall of Infamy in their house by Timmy after he stole Cosmo's wand. She then tried to steal Wanda's wand and would have succeeded in getting her revenge, but was thwarted by Wanda and put back into her painting, where she belonged.
- Timmy Turner
- Maryann bears a resemblance to Rhoda Penmark from The Bad Seed.
- She is arguably one of the most evil godchildren Cosmo and Wanda ever had and (possibly) one of the most evil villains in the series (alongside with Future Vicky and The Destructinator), because she actually had Archduke Ferdinand and his wife, Sophie, assassinated by magic and started World War I, whereas in actual history, Archduke Ferdinand and his wife were assassinated by Gavrillo Princip.