Slowing Charm

"Chasers were also becoming increasingly irritated by the necessity of diving continually towards the ground to retrieve the Quaffle and so, shortly after the Quaffle's change of colour, the witch Daisy Pennifold had the idea of bewitching the Quaffle so that if dropped, it would fall slowly earthwards as though sinking through water, meaning that Chasers could grab it in mid-air."

- Description of the spell's invention

Arresto Momentum is the incantation of a charm that can be used by a witch or wizard to slow the movement of an object. It is taught in second year Charms class at Hogwarts School of Witchcraft and Wizardry.

Known practitioners

 * Albus Dumbledore
 * Daisy Pennifold
 * Filius Flitwick
 * Hermione Granger
 * Unnamed referee in the 2014 Quidditch World Cup

Etymology

 * Likely the combination of two words; the Anglo-French "arester", meaning "to bring to a stop", and the Latin "Momentum", meaning "the force or strength gained whilst moving". Literal translation: "bring its momentum to a stop".

Behind the scenes

 * An alternative spelling, "Arresto Momento", is given in the seventh video game and first LEGO game.
 * This spell was meant to be in the Game Boy Advance version of the video game adaptation of Harry Potter and the Goblet of Fire. This is evidenced by the game's, which is inaccessible during normal gameplay but can be accessed via a cheating device such as an Action Replay. One of the options is a list of all of the text in the game, with "Arresto Momento" (using the alternate spelling mentioned above) being listed along with the game's other spells.
 * In the fifth and eighth films, the spell's effect is to directly stop movement as opposed to merely slowing it.

Appearances

 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Prisoner of Azkaban (film)
 * Harry Potter and the Goblet of Fire (video game)
 * Harry Potter and the Order of the Phoenix (film) 
 * Harry Potter and the Deathly Hallows: Part 1 (video game)
 * Harry Potter and the Deathly Hallows: Part 2
 * Quidditch Through the Ages (real)
 * LEGO Harry Potter: Years 1-4
 * LEGO Harry Potter: Years 5-7
 * Pottermore

Notes and references
Aresto Momentum Aresto Momentum Arresto Momentum