Musannaf Ibn Abi Shayba 3:592

Abdah ibn Sulayman narrated to us, from Ibn Abi Arubah, from al-Qasim ibn Amr, from Abu Ja’far, that the Prophet (peace and blessings of Allah be upon him) saw a man pecking with his head during his prostration. He said: "If this man were to die while this is his prayer, he would die upon other than my religion."