Shrinking Charm

"These straightforward but surprisingly dangerous charms cause certain things to swell or shrink. You will be learning both charms together, so that you can always undo an over-enthusiastic cast. There is thus no excuse for having accidentally shrunk your homework down to microscopic size or for allowing a giant toad to rampage through your school’s flower gardens."

- Miranda Goshawk

The Shrinking Charm (Reducio) is a charm that enables a witch or wizard to decrease the apparent physical size of the target, both internally and externally. It also can act as the counter-spell for the Engorgement Charm, causing the Engorged object to return to its original size.

The Shrinking Charm was used as the potion-making spell for the Shrinking Solution.

Known practitioners

 * Arthur Weasley
 * Bartemius Crouch Jr.
 * Harry Potter
 * Poppy Pomfrey

Etymology
The incantation is a Latin word meaning "to reduce" or "is reducable", fitting for this spell's effects.

Behind the scenes

 * In Harry Potter and the Deathly Hallows: Part 1 the scene in which the spider is enlarged is replaced by a mirror scene including Bluebell Flames.
 * The effects of this charm bear great similarity to those induced by the incantation of Diminuendo, used by Nigel Wolpert in 1995.

Appearances

 * Harry Potter and the Philosopher's Stone
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Deathly Hallows
 * Harry Potter and the Deathly Hallows: Part 1
 * Wonderbook: Book of Spells
 * Wonderbook: Book of Potions