Chair-conjuring spell

There exists a transfiguration spell which is used to conjure chairs out of thin air, usually for the purpose of providing seating for people.

History
At the 1993 Christmas Feast at Hogwarts School of Witchcraft and Wizardry, Albus Dumbledore used to spell non-verbally to conjure a chair for Sybill Trelawney in the Great Hall. Dumbledore used this spell again on 12 August 1995 to conjure two armchairs for himself and Arabella Figg during the Disciplinary hearing of Harry Potter in Courtroom Ten.

In December 1995, Minerva McGonagall conjured two chairs for Harry Potter and Ronald Weasley in the Headmaster's Office following the Attack on Arthur Weasley in the Department of Mysteries. In January 1996, Arthur Weasley used this spell to conjure several chairs for his family and friends are they were visiting him in St Mungo's Hospital for Magical Maladies and Injuries.

On 30 June 1997, after the Battle of the Astronomy Tower, Poppy Pomfrey conjured a single chair for Minerva McGonagall in the Hospital Wing.