Lockhart's use of this made-up spell was apparently well-known, as a question on the 1996 Theory of Charms O.W.L. asked whether Peskipiksi Pesternomi was a genuine charm or not, and required the answerer to come up with a valid incantation that would have the actual desired effect.
It had absolutely no effect whatsoever on the pixies Professor Lockhart had released to fly wild throughout the classroom, resulting in Lockhart fleeing and leaving Harry Potter, Ronald Weasley and Hermione Granger to "nip the rest back in their cages."
It is probable that this spell would not be effective in any case, as Professor Lockhart had presumably invented it in that same class, with no forewarning and no indication that it would be successful.
- Harry Potter and the Chamber of Secrets (First appearance)
- Harry Potter and the Chamber of Secrets (film)
- Harry Potter and the Chamber of Secrets (video game) (GBC version)
- Harry Potter and the Order of the Phoenix (film) (Mentioned only)
- LEGO Harry Potter: Years 1-4
- Pottermore (Mentioned only)