Furnunculus Curse

From UnknowableWiki

The Furnunculus Curse is a spell that causes boils to appear on its victim.

Mentions of the Furnunculus Curse in the series:

• Fred and George Weasley presumably use the curse to cover themselves in boils (after which they jump out from behind statues) in an effort to cheer up their sister Ginny during her first year at Hogwarts, when she is visibly upset by the Petrifications of Muggle-borns (CS11).
• Harry Potter attempts to cast the Furnunculus Curse on Draco Malfoy, but his spell ricochets off the spell Malfoy fires at him at the same time and hits Gregory Goyle instead (GF18).
• Harry casts the spell against Vincent Crabbe after Draco Malfoy incenses the Trio with his derogatory remarks about Cedric Diggory and what Voldemort's return will mean for Harry and his friends. George Weasley, who was nearby, attacks Crabbe at the same time with the Jelly-Legs Jinx; the combination of the two curses causes little tentacles to sprout on the Slytherin's face (GF37).