Bhairavi is a fierce and terrifying aspect of the
Devi virtually indistinguishable from
Kali, except for her particular identification as the consort of the
Bhairava.
-Wikipedia
Here She is depicted meditating in a cremation ground, symbolic of Her annihilation of materialistic attachments. Her appearance is terrifying to discourage demonic forces.
Her husband, Bhairava (a form of Lord Shiva who incarnates on the Earth) is shown seated on the left, wearing only ashes and a garland of skulls.