For instance, the spell's light forces ghouls to retreat and hinkypunks to solidify, and therefore can be used as a defensive measure. Also, the charm is excellent for charging crystal balls with light.
During the 1993-1994 school year, Professor Charity Burbage, who replaced a wizard as Professor of Muggle Studies class at Hogwarts School, placed a spellbook detailing the use of this spell in the Muggle Studies Classroom at Hogwarts Castle for unknown reasons, presumably so that she could use it.
During that year, third year Gryffindor student Ronald Weasley found Professor Burbage's spellbook and took it. He then proceeded to read the book and learn this Lumos Duo spell, and used it against several hinkypunks. He also used it to free Neville Longbottom from the ghoul in the classroom, who was harassing him.
Behind the scenes
- This charm does not appear in any of the books or films but only in the third video game in the video game series. It can only be used by Ron Weasley and not by any of the others, even though Harry in the previous game often made use of it and during most of the third year.
- Harry Potter and the Prisoner of Azkaban (video game) (First appearance)