J.K. Rowling has a Halloween treat for her Harry Potter fans that will be posted on pottermore.com on the Oct. 31. 

The piece will feature the background story of everyone's favorite witch and former Hogwarts professor to hate: Professor Dolores Umbridge. Harry Potter fans first met her in "Harry Potter and the Order of Phoenix" as the Minister for Magic's Senior Undersecretary and have been intrigued by her ever since.  

"The new exclusive J.K. Rowling content provides a rich, 1,700-word back story about Umbridge's life filled with many new details, as well as Rowling's revealing first-person thoughts and reflections about the character," reveals pottermore.com.

"Umbridge is not only one of the most malicious Potter characters, she is the only person other than Lord Voldemort to leave a permanent physical scar on Harry."