Mary Shelley (born 1797) is one of the TV-original characters not present in the preceding book series. She is best known for being the author of "The Modern Prometheus", better known as "Frankenstein". She was the daughter of philosophers William Godwin and Mary Wollstonecraft.
A preview of her episode, I Am Mary Shelley was aired 9am EST on Friday 20 September 2019 before Pinkalicious & Peterrific. It shows her exploring the general themes of what would be included in Modern Prometheus, though without the entirety of its horrific specifics. Later, her episode aired as a sneak peek on October 25, 2019, during the PBS Kids Family Night Halloween Marathon, right after Wild Kratts: Creepy Creatures. It is also available to stream online.
In her episode, the Riddles meet her in 1805 when she would've been ~8 years old, so her name would have actually been Mary Godwin, since she didn't marry Percy Shelley until 1816 when she was 19 years old.
Despite that, Mary does not appear to react with any kind of confusion when Yadina says "bye Mary Shelley!" directly adjacent to her.
Mary began writing the novel when she was 18 and it was published anonymously when she was 20 (in January 1818) and her name didn't appear on the book until the second edition in 1823.
She is voiced by Afrodite Antonopolous-Drossos.
As a child, Mary has dark brown, shiny wavy hair. She wears a dark green dress with a white collar and a light green gem on it. Her belt and flats are both olive green.