Bubble-Head Charm
Type	Charm
Effect	Creates bubble protecting the head

[Source]

The Bubble-Head Charm (incantation unknown) is the most effective spell for breathing underwater or in any environment where fresh air is at a premium, allowing one a supply of oxygen. It causes a protective bubble to form about the caster's head, like a helmet. This bubble may allow the caster to breathe underwater or protect the head from falling objects.

Known uses

• It was used by Cedric Diggory and Fleur Delacour during the Second Task of the Triwizard Tournament to enable them to breathe underwater.
• Hogwarts School of Witchcraft and Wizardry students also used this spell in 1996 after the departure of Fred and George Weasley, when it became fashion to throw Dungbombs and Stink Pellets in the corridors of Hogwarts.

  

Behind the scenes

• A similar spell called Ebublio is seen in the Harry Potter video games.
• In the films, the charm creates a bubble around the mouth and nose, similar to an oxygen mask, not the entire head.

Appearances

• Harry Potter and the Goblet of Fire (First appearance)
• Harry Potter and the Goblet of Fire (film)
• Harry Potter and the Order of the Phoenix
• Wonderbook: Book of Spells