Harry Potter is owned by JK Rowling
Chapter 2: Philosopher's Stone
"speech"
(thoughts)
Dear Professor Dumbledore,
Professor Quirrel, the new Defense against the Dark Art teacher you have hired, is possessed by Lord Voldemort. A simple levitation charm on his hat will reveal that Tom is growing out of the back of Quirrel's head.
Also, if you do not tell Harry Potter about the prophesy by the end of the year, then I shall tell him next year when I arrive at school.
Sincerely,
Luna Lovegood
Dumbledore arranged for Professor Quirrel to arrive at Hogwarts a week early. When Quirrel timidly walked into the great hall a dozen Aurors were waiting for him, spread out in all corners of the room. When Quirrel got to the center of the room, Dumbledore levitated his turban, revealing the hideous face growing out of the back of his head. In the ensuing battle five Aurors were killed and Quirrel's body had to be destroyed before Voldemort could be banished from Hogwarts.
Sirius Black became the Defense Against the Dark Arts teacher for that year. As much as Sirius liked getting to know his godson better, he found that deep in his heart of hearts, he hated teaching and he asked Dumbledore to find a new DADA teacher for the next year.