Tantrasara mentions the iconography from the goddess Bagulamukhi. It mentions which the goddess is seated over a golden throne floating in the amazing ocean. A different etymology suggests that valga indicates "to paralyze" and symbolizes the strength of stambhana, "paralysis" which the goddess is alleged to grant; this concept https://gunnerlqswx.onesmablog.com/5-essential-elements-for-baglamukhi-73180376