Disarming Charm

"A handy (even life-saving) spell for removing an object from an enemy's grasp."

- Description of the charm The Disarming Charm, also known as the Expelliarmus Spell or Disarming Spell (Expelliarmus) was a defensive charm which forced the victim to release whatever they were holding at the time. It is common to see this spell used in duels, to make an opponent release their wand.

History
It is not known precisely who created the Disarming Charm. Some wizarding historians claim that it may have been invented by Merlin himself, others claim that its first widespread use was in Madagascar in the 11th century. Even if any of this is true, the fact remains that it was not very popular until 1379, when Elizabeth Smudgling — the most likely inventor, in the opinion of Miranda Goshawk — used it in a duelling contest in Dartmoor.

It became Harry Potter's signature spell, and it notably caused the death of Lord Voldemort during the Battle of Hogwarts by rebounding his Killing Curse.

Effects
"The Disarming Charm lies at the heart of a good duelling technique. It allows the duelist to rebound an opponent's spell in the hope that the rebounded spell will strike the opponent and leave him or her vulnerable to further attack."

- Miranda Goshawk

The Disarming Charm causes whatever an opponent is holding at the time — usually a wand — to fly high out of their reach.

The Disarming Charm always appears as a jet of red light; indeed, this is one of the things that makes it recognisable before the effects of the charm are seen. However the intensity of the light appears to correspond to the strength of the spell as a weak/moderate one creates a small flash of white light whereas a more powerful version manifests as a bright jet of scarlet light. Another notable effect of the charm is that if multiple charms are used on the same target, the target will be disarmed, but at the same time will be blasted backwards, as seen when Harry, Ron and Hermione all used the Disarming Spell at once on Severus Snape in the Shrieking Shack.

Priori Incantatem


If two wands with the same core are forced to do battle with each other, the effect is a magical connection called Priori Incantatem. When Priori Incantatem occurred between Lord Voldemort and Harry Potter, the latter was using the Disarming Charm, a much weaker spell than the former.

Known uses and practitioners
"They made the most of the last few hours in which they were allowed to do magic before the holidays... and practised disarming each other by magic. Harry was getting very good at it."

- Fred, George, and the trio's last few hours before they return home for the holidays

Etymology
Latin expellere (ex = out, pellere = to drive), meaning "to drive out" and "arma" meaning "weapon". Expelliarmus actually means 'to drive out the weapon'.

Behind the scenes
"Then a blinding, jagged jet of white light flew through the air: Harry thought of lightning, but Snape had dropped to his knees and his wand had flown out of his hand"

- Dumbledore's use on Snape


 * This is the signature spell of Harry Potter.
 * In the films only when a witch or wizard is locked in the Priori Incantatem is the spell scarlet. When not locked in combat it's always just a blue or white flash that will either connect with the target's hand and force the wand out of their hand or will blast them off their feet, sometimes unconscious.
 * When Dumbledore used this on Snape, it appeared as white lightning, and hence was probably a variation of it rather than the spell itself, or else an entirely different disarming spell.
 * The charm is described in The Standard Book of Spells, Grade 2, and has a spellbook purely for itself.
 * In the second film, it appears as a golden ring; from the fifth film onward it was a ball or flash of blue light.
 * In the video games, mainly he console versions of the first and second games, the Disarming Charm worked rather like a Shield Charm, rebounding an opponent's spells upon them. This is actually also the describing of the spell in the The Standard Book of Spells series. This was mainly due to the lack of being able to disarm in past video games.
 * However, the spell returned to its more offensive use by the Order of the Phoenix game, though the GBC version of the Chamber of Secrets game also follows this scheme.
 * Also in the console version of the second game, it's possible to catch and deflect spells not only cast by prefects in the PS2 version, but it's also possible to do so on one's own backfired spell. This only works on Flipendo and Incendio however, as the other projectile spells will pass through. In the case of the former, it moves rather fast so tight timing to activate the charm is needed.
 * The Disarming Charm is referenced on Doctor Who, when Shakespeare uses it to conclude a formula used to banish the villains from earth. The Doctor (played by David Tennant) smiles after the villains are beaten and says: "Good old J.K.", referencing the author of the Harry Potter series.
 * As seen in, it is possible to disarm and take ownership of one's wand without using the spell, as demonstrated by Harry, who forcefully disarmed Malfoy with his bare hands to take the latter's wand.
 * In the film versions of, Hermione Granger used the spell to make Mundungus Fletcher's wand fly over to her for her to catch it, which also happened when Harry Potter defeated Tom Riddle during Voldemort's Last Stand, in a similar way to the Summoning Charm.

Notes and references
Encantamiento desarmador Expelliarmus Sortilège de Désarmement Aseistariisuntaloitsu Incantesimo di Disarmo Expelliarmus Экспеллиармус Expelliarmus