Black Jambhala is a manifestation of buddha Amoghasiddhi. He has one face with three eyes, two hands in which he holds a mongoose that spits jewels and a skull cup or sometimes a pot of jewels. He is adorned with snakes and stands over the body of the Lord of Wealth (Yellow Jambhala). The above sculpture shows him with a small skull-crown and flaming hair standing straight on his head.
Here we can see that he has a sitting buddha on top of his head and that his victim is indeed Yellow Jambhala, who holds a mongoose in one hand and a citrus fruit in the other.
On this sculpture, he has the effigy of a buddha in his chignon and stands on an Indian-style lion-throne with an arch decorated with other figures.