This spell is a transfiguration spell which turns books into other books.

In the 1995–1996 school year when Dolores Umbridge saw Harry Potter and the other Dumbledore's Army members walking towards Hogwarts Castle from the Clock Tower Courtyard carrying defensive books, she used this spell to turn them into Dark Arts Defence: Basics for Beginners.

Behind the scenes

  • While the existence of the spell can be considered canon, its use by Umbridge cannot, as there is no indication in the novel that Umbridge caught Dumbledore's Army at any of their activities prior to Marietta Edgecombe's betrayal of the group.
    • Although she didn't use this spell or let the members of the Army see her in the film adaptation of Harry Potter and the Order of the Phoenix, she, along with Argus Filch, sees them from the clock face of the Clock Tower and tells Filch to watch over them.