In J.K. Rowling’s fantasy novel Harry Potter and the Prisoner of Azkaban, Harry Potter’s magical map is called the Marauder’s Map.
Fred and George Weasley give Harry the map after taking it from Filch’s office. It reveals every corridor, classroom, secret passage, and person within Hogwarts Castle and its grounds. The map is activated and closed by spoken phrases that involve insulting its user.
Its creators were four Hogwarts students who used the nicknames Moony, Wormtail, Padfoot, and Prongs. They were Remus Lupin, Peter Pettigrew, Sirius Black, and James Potter. The map is more than a normal plan because it tracks human footsteps and exposes people who are hidden or using invisibility.