According to the Shiva Purana, Lord Brahma and Lord Vishnu once argued about which of them was greater. Suddenly an endless pillar of fire appeared between them, a vast linga of light whose beginning and end could not be seen.
They agreed that whoever found the end of this pillar would be the greater. Lord Vishnu took the form of a boar, Varaha, and went downwards, while Brahma flew upwards as a swan. Even after searching for ages, neither found the end. Lord Vishnu humbly admitted the truth, but Brahma claimed to have seen the top, with a ketaki flower as his false witness.
Then Lord Shiva emerged from that pillar of light. He cursed Brahma and the ketaki flower for their lie and praised Lord Vishnu's truthfulness. The night of this appearance is celebrated as Mahashivratri.
In this form of light, Shiva is worshipped across India as the twelve Jyotirlingas. Among them, Somnath, the first Jyotirlinga, and Nageshwar near Dwarka are both in Gujarat.