Marion Hawthorne is the main antagonist of the 1964 novel Harriet the Spy by Louise Fitzhugh, the 1996 movie of the same name and the 2010 TV movie adaptation Harriet the Spy: Blog Wars.
She was played in the 1996 film by Charlotte Sullivan and in Harriet the Spy: Blog Wars by Vanessa Morgan.
Harriet the Spy
In the 1996 movie, she is the snobby adversary of Harriet M. Welsch who exposes the honest and hurtful contents of Harriet's notebook to their classmates, causing Harriet to be ostracized for them. She is usually responsible for circumstances under which Harriet would suffer at school for them. In the end, Harriet was forgiven by the classmates but Marion does not forgive and was not punished for her doings, due her charm around adults.
Harriet the Spy: Blog Wars
In the 2010 film, Marion is still as snobby as ever (if not more so). She is now competing with Harriet to become the class blogger. She gets the jump on Harriet by blogging first, and later finds out that Harriet's father is producing the latest Skander Hill flick. After Harriet starts blogging about Skander Hill, she is immediately suspicious and claims that Harriet should provide proof that she actually knows Skander. When Harriet posts Skander's rant on her blog, Marion posts it online for everyone to see, thus violating the rules in a possible last-ditch attempt to ruin her. In the end, she loses the blog and possibly her popularity.