Criobolium, in the ancient religion of Asia Minor, the sacrifice of a ram and the bathing of a devotee in its blood, in the cult of the Phrygian deities Attis and Cybele, the Great Mother of the Gods. The ceremony may have been instituted on the analogy of the Taurobolium, or bull sacrifice, which it probably resembled. When it was performed in conjunction with the Taurobolium, the altar was usually inscribed to both the Great Mother and Attis, whereas the inscription was to the Mother alone when only the Taurobolium was performed.