Griffin-shaped knocker

This knocker rests on the office door of all past and present Hogwarts Headmasters. It is made of brass and is in the shape of a Griffin. It would have been used a great deal of times since its creation, due to the fact that most visitors will have used it as a precursor to entering the Headmaster's/Headmistress office. It is known that Harry Potter once avoided its use (involuntarily) by standing outside Professor Dumbledore's office, listening to a conversation between Dumbledore, Cornelius Fudge, and Bartemius Crouch Jr. (acting as Alastor Moody at the time), when Bartemius noticed Harry's presence with Alastor Moody's Magical Eye, thus opening the door for Harry.

Users of the Knocker

 * Unidentified Hogwarts Headmistress
 * Dexter Fortescue
 * Phineas Nigellus Black
 * Armando Dippet
 * Albus Dumbledore
 * Severus Snape
 * Minerva McGonagall
 * Minerva McGonagall's successor
 * All enterers of the Headmaster's office.

Behind the scenes

 * Before the release of Harry Potter and the Deathly Hallows, many people assumed that the griffin-shaped knocker was one of Lord Voldemort's Horcruxes. It was known that Voldemort was keen on having one of his seven Horcruxes to represent something from each Hogwarts House. He had chosen Hufflepuff's cup, Slytherin's locket and Ravenclaw's diadem to be Horcruxes so it was thought that the "Griffin Door" (Gryffindor) knocker was made a Horcrux by Voldemort when he applied for a job at Hogwarts.

Appearances

 * Harry Potter and the Chamber of Secrets
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Order of the Pheonix
 * Harry Potter and the Half-Blood Prince