SB 10.88.17
ity adistas tam asura
upadhavat sva-gatratah
kedara atma-kravyena
juhvano gni-mukham haram
Translation:
[Sukadeva Gosvami continued:] Thus advised, the demon proceeded to worship Lord Siva at Kedaranatha by taking pieces of flesh from his own body and offering them as oblations into the sacred fire, which is Lord Siva’s mouth.