Langlock

Langlock is a jinx or hex that causes one's tongue to affix to the roof of the mouth. It was invented by Severus Snape while he was a student at Hogwarts School of Witchcraft and Wizardry.

Known uses
Harry Potter used Langlock on Argus Filch, and again on Peeves.

Etymology
The word langue is the root for tongue.

Appearances

 * Harry Potter and the Half-Blood Prince