What is the torment of the grave?

A Muslim must believe that the grave is the first stage of the Hereafter, and that a person in it will be either in a garden from the gardens of Paradise or a pit from the pits of Hellfire. It has been authentically narrated in a Hadith that when a disbeliever or an evildoer dies, his soul is returned to his body, and two angels come to him and ask him about his Lord and his Messenger. He replies, "Hah, hah, I don't know." Then a caller announces, "My servant has lied!" So, a bedding of fire is spread for him, and he is clothed from it. A door to Hellfire is opened for him, and its heat and poisonous winds reach him. His grave is constricted upon him until his ribs intertwine. Also, a blind and mute individual comes to him with an iron hammer and strikes him with it, turning him into dust, then his soul is returned. These are among the unseen matters that must be believed in.