Concealment and Disguise

• Incantation: Varies widely depending on the specific method. Includes incantations for the Disillusionment Charm, Muffliato Charm, and the Fidelius Charm, among others.
• Pronunciation: Varies
• Wand Movement: Varies
• Light: Varies. Many concealment spells, such as the Disillusionment Charm, produce no visible light to avoid drawing attention.
• Effect: To hide, obscure, or alter the appearance, presence, or properties of a person, creature, object, or location, making them difficult or impossible to perceive or identify through normal or magical means.
• Type: A broad category of magic encompassing Charms, Transfiguration, and Potions. Some forms are also innate abilities.

Concealment and disguise are fundamental magical practices, used extensively for secrecy, protection, espionage, and crime. Their applications range from simple hiding spells to complex, long-term impersonations. Invisibility and Obscurement

• Invisibility Cloak: The most famous tool for concealment. Harry Potter's cloak, one of the Deathly Hallows, provided near-perfect invisibility that did not fade over time. He used it countless times to navigate Hogwarts undetected, spy on his adversaries, and travel unseen during the hunt for the Horcruxes. Albus Dumbledore also possessed it for a time, and Barty Crouch Jr. used a lesser-quality cloak to hide at the Quidditch World Cup.
• Disillusionment Charm: This charm does not grant true invisibility but causes the target to blend seamlessly with their surroundings, like a chameleon. Alastor Moody cast it on Harry Potter during their flight from Number Four, Privet Drive to Number Twelve, Grimmauld Place. Hermione Granger routinely used it to protect the trio's campsite during their search for Horcruxes.
• Peruvian Instant Darkness Powder: A substance imported from Peru by Fred and George Weasley and sold at Weasleys' Wizard Wheezes. It creates a sudden, impenetrable darkness, allowing for a quick escape. Draco Malfoy used it on the Hogwarts Express to ambush Harry and later to help Death Eaters enter Hogwarts.
• Protective Enchantments: A layered series of charms can be used to hide a location. Hermione Granger protected the trio's tent with spells like `Salvio Hexia`, `Protego Totalum`, `Repello Muggletum`, and the `Muffliato Charm` to make it unnoticeable to outsiders.

Disguise and Impersonation

• Polyjuice Potion: A complex and time-consuming potion that allows the drinker to assume the physical appearance of another person for one hour. It was used by Harry Potter, Ron Weasley, and Hermione Granger to infiltrate the Slytherin common room; by Barty Crouch Jr. to impersonate Alastor Moody for an entire school year; and by members of the Order of the Phoenix during the Battle of the Seven Potters. The trio also used it to infiltrate the Ministry of Magic and Gringotts.
• Animagus Transformation: The ability to transform into an animal at will. As it is a physical transformation, it is an effective disguise. Peter Pettigrew hid as the Weasley family's pet rat, Scabbers, for twelve years. Sirius Black used his dog form to escape Azkaban and remain hidden. Rita Skeeter used her unregistered beetle form to spy for stories for the Daily Prophet.
• Metamorphmagus: An innate ability to change one's physical appearance at will without a potion or spell. Nymphadora Tonks frequently used this ability as an Auror and for personal expression, changing her hair colour and nose shape.
• Human Transfiguration: Extremely advanced magic that can alter a person's features. It is considered difficult and dangerous. Hermione Granger used a Stinging Jinx to disfigure Harry's face as a temporary disguise when they were captured by Snatchers.

Location Concealment

• Fidelius Charm: An immensely powerful and complex charm used to conceal a secret within the soul of a single living person, the Secret-Keeper. The location hidden by the charm becomes magically undiscoverable to anyone unless the Secret-Keeper voluntarily reveals it. It was used to hide the Potters' home in Godric's Hollow, the headquarters of the Order of the Phoenix at Number Twelve, Grimmauld Place, and Bill Weasley and Fleur Delacour's home, Shell Cottage.
• Unplottable Locations: Some locations, like Hogwarts, are made Unplottable, meaning they cannot be marked on any map, magical or Muggle.

The difficulty of learning concealment and disguise magic varies greatly. The Disillusionment Charm is covered in the O.W.L. curriculum, while brewing Polyjuice Potion is a highly advanced skill. Becoming an Animagus is exceptionally difficult and requires registration with the Ministry of Magic. Several methods exist to detect and counter concealment:

• Spells: The Homenum Revelio spell reveals human presence in an area. `Specialis Revelio` can be used to identify enchantments on an object.
• Magical Objects: The Marauder's Map showed the location of every person within Hogwarts, regardless of any physical or magical disguise like an Invisibility Cloak or Animagus form. Alastor Moody's Foe-Glass would show the figures of his enemies, even if hidden. Probity Probes were used at Gringotts to detect hidden magical objects or enchantments.
• Magical Beings and Locations: Dementors are not fooled by physical disguises like the Animagus transformation, as they sense emotions rather than see. The Thief's Downfall at Gringotts is a waterfall that washes away all magical concealment.
• Unique Senses: Alastor Moody's magical eye could see through Invisibility Cloaks and other forms of magical concealment. Snakes like Nagini appear to be able to detect people through a combination of heat-sensing and magical perception.

• Conceal: From the Latin concelare, meaning “to hide completely,” from com- (together) and celare (to hide).
• Disguise: From the Old French desguiser, meaning “to change one's style of dress or appearance.” This reflects the core purpose of altering one's identity.

• In the film adaptations, Harry Potter's Invisibility Cloak is depicted as a silvery, liquid-like fabric with intricate patterns, which becomes translucent when worn. This is a visual interpretation, as the book describes it as being “fluid and silvery” but does not detail its specific appearance when active.
• J.K. Rowling has clarified that when a Secret-Keeper dies, everyone to whom they have revealed the secret becomes a Secret-Keeper in turn. This is how the Order of the Phoenix could continue using Number Twelve, Grimmauld Place as a headquarters after Albus Dumbledore's death. (J.K. Rowling interview)