Musnad Ahmad 31:344

Abu Abd al-Rahman narrated to us, Sa'id ibn Abi Ayyub narrated to us, he said: I heard Abu al-Samh say: I heard Abu al-Haytham say: I heard Abu Sa'id al-Khudri say: The Messenger of Allah, peace and blessings of Allah be upon him, said: "There shall be unleashed upon the disbeliever in his grave ninety-nine dragons, which shall bite him until the Hour is established. If one of those dragons were to blow upon the earth, it would not sprout any greenery."