Protego horribilis

Protego Horribilis is a stronger version of the Shield Charm which protects a very large area against highly Dark Magic. It causes anything within the ranges of Dark Magic to rebound off the shield.

Known uses

 * This spell was cast by Headmaster Albus Dumbledore to protect the boundaries of Hogwarts Castle from the Death Eater forces in the early hours of 1 September, 1996. Indeed a Death Eater tried to cross the barrier on a broom but was repelled by the shield.
 * This spell was cast by Charms Master Filius Flitwick to protect the boundaries of Hogwarts Castle from the Death Eater forces in the late hours of 1 May, 1998, prior to the Battle of Hogwarts that started at midnight the next day.

Etymology
Latin Protego, "I protect", and Horribilis, "horrible, frightful, dreadful".

Behind the Scenes

 * Protego Maxima replaced this book-spell in the film. It is another variant of the Shield Charm.

Appearances

 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Deathly Hallows

Notes and references
Varjelum kamalus Protego horribilis Протего хоррибилис