It is a Beast Spirit of the earth element which needs the user to constantly eat to gain more power, that's why you always see Elder Xuan with chicken and a wine gourd. It's a Spirit that only the ones that posses the bloodline of the Taotie could awake.
When it is activated, Elder Xuan’s aged back suddenly arched upwards, and his oil-stained, tattered clothing immediately split open. The muscles on his back swelled up at shocking speed, and in the blink of an eye, he bulked up to at least twice his previous size. The strangest thing was that one long, screw-shaped horn also grew from either side of his head.