Hatkeshwar Mahadev is one of the manifestations of Hindu God Shiva. Hatkeshwar is the patron deity of the Nagar community in India . There is an interesting story that explains the appearance of Shiva as Hatkeshwar Mahadev.
After death of Sati, Shiva lost his interest in worldly life and started roaming around in inept state. He roamed naked all around the world and once he walked into an ashram of a group of sages. Shiva who looked like a naked yogi garnered attention of all the people. The wives of the sages were attracted to Shiva and the husbands noticed lust in their wives eyes for Shiva.
The sages considered this naked yogi as a distraction and cursed him. They cursed that the naked yogi become impotent. This caused great upheaval in nature as Shakti cannot reproduce without Shiva. All creation came to a standstill. There were no births and only there was death all around.
Finally, Brahma asked Shiva for a solution. He said that when he is worshipped in Shivalinga form the world order will be restored. Brahma created a Shivlinga made up of gold, i.e Hatak. This shivlinga was called Hatkeshwar.