Marauder's Map

At first glance, the Map is simply a blank piece of parchment; but when the user points his his wand at the map and says, "I solemnly swear that i am up to no good", the message "Messrs. Moony, Wormtail, Padfoot and Prongs, purveyors of aids to magical mischief-makers, are proud to present the Marauder's Map." and a detailed layout of Hogwarts appears. Saying, "Mischief managed!" while pointing one's wand on the parchment returns the map to its original blank state. The map displays the location of everyone within the castle and its grounds, and includes the location of secret passageways and instructions on how to access them. Several locations like the Room of Requirement and the Chamber of Secrets do not appear on the map. Also, animagus disguises, polyjuice potions, and invisibility cloaks cannot fool the map.