The blessings of Maa Baglamukhi develop a divine protective shield in the form of the aura all over someone thereby safeguarding him/her from malefic energies in the form of black magic spells or evil eye. Another etymology suggests that valga means "to paralyze" and symbolizes the strength of stambhana, "paralysis" https://www.youtube.com/shorts/5VeSyP9JRw0