Bubble-Head Charm

The Bubble-Head Charm (incantation unknown) is a spell that creates a bubble of air around the caster's head, giving the caster the appearance of inverting a fishbowl and placing it on his or her head. It is first used in Harry Potter and the Goblet of Fire by Cedric Diggory in the Second Task of the Triwizard Tournament to enable him to breathe underwater.

Students also used this spell a great deal in Order of the Phoenix after the departure of Fred and George Weasley, when it became fashionable to drop Dungbombs and Stink Pellets in the corridors of Hogwarts.