Musnad Abu Ya'la al-Mawsili 42:394

Narrated to us Zuhayr, narrated to us Ibrahim Abu Ishaq al-Taliqani, narrated to us Ibn al-Mubarak, from Sa'id ibn Yazid Abu Shuja', from Abu al-Samh, from Abu al-Haytham, from Abu Sa'id al-Khudri, from the Prophet (peace be upon him), who said regarding [the verse]: "And they therein will be *kalihun* (grimacing/distorted)": The believers said: "The Fire distorts them, so his upper lip shrinks until it reaches the middle of his head, and the other [lip] hangs down until it strikes his navel."