Goddess Kali is regarded as the most fierce and destructive form of Shakti. She has a dark complexion, red eyes and has four arms. In one of Her hands She carries a sword (khadaga) and in another hand She carries the decapitated head of a demon. But in temples you will se her idol stepping over Lord Shiva.

This episode of Holy Tales by Himanshu Sharma will tell you the interesting story - why Kali stepped on Shiva's chest?