Densaugeo

"'Densaugeo!' screamed Malfoy. Jets of light shot from both wands, hit each other in mid-air, and ricocheted off at angles... Malfoy's hit Hermione... Hermione's front teeth - already larger than average - were now growing at an alarming rate; she was looking more and more like a beaver as her teeth elongated, past her bottom lip, towards her chin..."

- Draco Malfoy's use of the hex on Hermione

The Tooth-Growing Spell is a hex which causes the victim's two front teeth to enlarge grotesquely at an alarming rate. The incantation for this spell is Densaugeo.

Known uses
In 1994, Draco Malfoy tried to use this hex on Harry Potter, but it struck Hermione Granger instead. The effect of the charm made Hermione's teeth grow past her collar, though Professor Snape remarked that he saw no difference. This caused Hermione to burst into tears and run to the Hospital Wing. The hex is reversable, as Poppy Pomfrey was able to shrink Hermione's teeth back, probably with the Shrinking Charm. Although, as Hermione had felt that her front teeth were too big to begin with, she allowed them to be shrunk to almost a centimetre smaller than they were prior to the hex hitting her. It was also used in 1997 by Ted Tonks to regrow Harry Potter's tooth after the Battle of the Seven Potters.

Etymology
From Latin dens, "tooth," and augeo, "I increase" or "I enlarge."

Behind the scenes

 * The hex is included in the "5 Spell Pack" DLC for LEGO Harry Potter: Years 5-7. In the game, the hex not only enlarges teeth, it also makes the victim wear groucho glasses.
 * The Tooth-Growing Spell may be related to other spells that enlarge objects (e.g. the Engorgement Charm which enlarges objects in general).

Appearances

 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Deathly Hallows
 * LEGO Harry Potter: Years 5-7

Notes and references
Dentesaugmento Hammasiso