Half-Blood Prince
Scholastic
Chapter 12
Silver and Opals
Harry had already attempted a few of the Prince's self-invented spells. There had been a hex that caused toenails to grow alarmingly fast (he had tried this on Crabbe in the corridor, with very entertaining results); a jinx that glued the tongue to the roof of the mouth (which he had twice used, to general applause, on an unsuspecting Argus Filch); and perhaps most useful of all, Muffliato, a spell that filled the ears of anyone nearby with an unidentifiable buzzing, so that lengthy conversations could be held in class without being overheard. The only person who did not find these charms amusing was Hermione, who maintained a rigidly disapproving expression throughout and refused to talk at all if Harry had used the Muffliato spell on anyone in the vicinity.
Sitting up in bed, Harry turned the book sideways so as to examine more closely the scribbled instructions for a spell that seemed to have caused the Prince some trouble. There were many crossings-out and alterations, but finally, crammed into a corner of the page, the scribble:
Levicorpus (nvbl)
pg 238