Goddess Kali standing on Shiva is a popular image in Hindu tradition. Legend has it that after defeating Mahishasura and other demons, Goddess Kali was still outraged at the Adharma on earth. She continued destroying everything before her. All living beings were foreseeing eternal doom. To escape from the wrath of Goddess Kali they approached Shiva.
To stop Goddess Kali from destroying the cosmos, Shiva went into the battlefield and lied down motionless among the corpses of demons.
Goddess Kali moved across the corpses destroying and cutting them into pieces, suddenly she found herself standing on top of a beautiful male body. For a moment she stood still and then she looked down at the body and saw it was Shiva, her husband.
When she realized she was touching her husband with her feet, Goddess Kali stretched out her tongue in shame and the destruction came to an end.
Shiva then pacified the Goddess and danced with her. Together they started creation again and made the world free of Adharma.