Shri Guru Pradosh Vrat Katha

Once, a fierce battle broke out between Indra's forces and the army of Vritrasura. The gods defeated and utterly destroyed the demon army. Seeing this, Vritrasura, greatly enraged, took up the fight himself, and, through demonic illusion, assumed a fearsome form. All the gods, terrified, took refuge with their guru, Brihaspati. Brihaspati said, 'First let me tell you the true history of Vritrasura. Vritrasura is a great ascetic and man of discipline, who once performed severe penance on Mount Gandhamadan and pleased Lord Shiva.'

'In former times he was a king named Chitraratha. Once, travelling by his celestial chariot, he went to Mount Kailash, and there, seeing Mother Parvati seated on Shiva's left side, he mocked, "O Lord, being caught in delusion, we mortals remain in thrall to women, but it has never been seen in the realm of the gods that a woman sits embraced in an open assembly." Hearing Chitraratha's words, the all-pervading Shiva Shankar laughed and said, "O king, my way of seeing things is different, I have drunk the death-dealing poison Kalakuta itself, and yet you mock me like an ordinary man." Mother Parvati, enraged, said to Chitraratha, "O wicked one, you have mocked both the all-pervading Maheshwar and me, so I shall teach you a lesson such that you will never again dare to mock such holy ones, now take the form of a demon and fall from your chariot, I curse you." By this curse of Jagadamba Bhavani, Chitraratha was reduced to a demon's existence, and, born of the great penance of the sage Tvashta, became Vritrasura.'