Some forms of Mahakala are rarely seen, and almost exclusively on paintings.
This is the raven-headed form of Mahakala (with three eyes and flaming hair), also known as Kakamukha. He holds a flaying knife in his right hand and another object in the other (instead of the standard skull cup) .He is adorned with a five-skull crown, a garland of severed heads, bone jewellery, a Chinese-style flowing scarf.
He wears a tiger skin dhoti (the paws of the animal are showing below the garland of severed heads), a cross-belt with a raining-jewel pendant, and some kind of sash or belt ending with raining jewels.
Bernag Chen (“black cloak”) is a form of Mahakala proper to Tibet. He has one head with three eyes and flaming hair, two hands in which he holds a flaying knife and a skull cup, and two legs which stand on a victim. Surrounded with flames, he is adorned with the usual skull crown, garland of severed heads, bone jewellery, and wears a large cloak.
Here, Mahakala rides a tiger and holds a stick and a skull cup.