"Fleur Delacour, though she demonstrated excellent use of the Bubble-Head Charm, was attacked by grindylows as she approached her goal, and failed to retrieve her hostage. We award her twenty-five points. ... Cedric Diggory, who also used the Bubble-Head Charm, was first to return with his hostage, though he returned one minute outside the time limit of an hour.... We therefore award him forty-seven points."
-- Ludo Bagman after the 2nd Task of the Tri-Wizard Tournament
The Bubble-Head Charm encloses the head of the caster with a bubble of breathable air.
References from the canon
- Cedric used this spell to travel underwater and rescue Cho in the second task (GF26).
- Fleur used this spell to travel underwater when attempting to rescue Gabrielle in the second task (GF26).
- This became fashionable during the last month or so of Harry's fifth year, because Dungbombs and Stink Pellets were being used frequently in the corridors (OP30).
- During an alternate timeline caused by the use of the Experimental Time-Turner, Cedric Diggory is seen to use the charm during the Second Task of the Triwizard Tournament. Albus Potter and Scorpius Malfoy use an Engorgement Charm to enlarge the bubble-head so that Cedric floats away (CC2.20).
From the Web
"Bubble-Head Charm" from Harry Potter Wiki