Musnad Abu Ya'la al-Mawsili 161:64

Ishaq narrated to us, Sharik ibn Abdullah narrated to us, from Simak ibn Harb, from Abdullah, from al-Ahnaf ibn Qays, from al-Abbas ibn Abd al-Muttalib, regarding His saying: "And the Throne of your Lord will be borne above them that Day by eight [angels]." He said: "Eight angels in the form of mountain goats."