Hindu mythology, there are four yugas or eras: the Krita, Treta, Dwapara and Kali Yugas.
Kali the last of the eras is said to be full of evil. We are living in that era.
This Kali took the form of a low-bred person dressed as a king and was beating a cow and a
bull, when Parikshit saw him.
The bull had but one leg and the cow looked famished.
The cow was no other than Mother Earth and the bull, Dharma or moral law.
Unable to bear the pain, the animals shed tears.
Parikshit at once knew who all three were.