Legend of Moreshwar temple
It was predicted by Lord Brahma that Lord Ganesha would incarnate as Vinayak in the Kritayug, as Mayureshwar in Treta yug, as Gajanan in the Dwaparyug and as Dhumraketu in the Kalyug. All these incarnations are related to certain legends of Lord Ganesha killing various demons.
In the Gandaki Nagari of Mithila, a king named Chakrapani was ruling. He and his wife Queen Ugra were unhappy, as they did not have a child. The couple worshipped God Surya and the queen with the blessings of the Sun God became pregnant. But soon released the embryo in the sea as she could not bear the brilliance and the radiance of the embryo. From that embryo, brilliant son was born. The sea in the disguise of a Brahmin approached King Chakrapani with the child and gave the child to the King. As the child was born in the sea the king named him sindhu. Sindhu, after growing old and strong became more powerful by worshipping the Sun God as advised by his Guru Shukracharya. Lord Surya, as a boon gave the nectar to Sindhu and said that as long as the nectar remains near his navel he will not die. Sindhu thus received immortality and started attacking Gods like Indra, Vishnu etc. he defeated all of them and kept them in prison in his kingdom. The remaining gods worshipped Lord Ganesh and requested him to rescue them from the demon king sindhu. Ganesha pleased with their prayers, promised to take birth as Devi Parvati's son and kill the demon.
Parvati recited the ekakshari ‘OM' mantra to please the Lord and made a clay idol of Ganesha on the Bhadrapada shuddha Chaturthi Day and worshipped. The idol soon turned into a real child. When the child was ten years old, Shiva and Parvati along with their son decided to leave the mountain Meru and on their way to mountain kailash, Lord Ganesha defeated the demon Kamalasura with the help of Siddhi(the personified shakti) and Buddhi(the personified Intelligence). After this incident on their way, lord Ganesha found the Gandaki Nagari of the demon king Sindhu and decided to attack him with all the army of Shiva's attendants. He thus attacked Sindhu and at first killed the two sons of Sindhu. Sindhu was advised to release the Gods and Goddesses in prison and leave the battlefield by his father. But he did not listen to it and continued the battle. Lord Ganesha removed the nectar from his navel with his Parashu and killed him. During this battle, Lord Ganesha was riding a peacock and therefore he got the name ‘Mayureshvar', the one who rides a peacock. Mayureshvar decided to reside at Morgaon, for the sake of his devotees.
Another legend that accounts for Lord Ganesh's Mayureshwar is:
Sage Kashyap had two wives, Kadru and Vinita. Kadru's sons who were the serpents, held Vinita's sons Shayen, Sampati and Jatayu who were the birds, captive. Vinita, their mother was very hurt by this. As a consolation, Sage Kashyap gave Vinita a boon of having one more son also in the form of a bird. When this son was in the egg stage, Lord Ganesh broke the egg, and a peacock emerged from the egg. The newborn peacock and Ganesh battled with each other. Vinita the mother had to intervene to end this battle. Ultimately her peacock son chose to be Ganesha's vehicle and laid down the condition that Ganesh would be known by the peacock's name. Thus Ganesha took the name Mayureshvar. Moreshwar is a local variation of the name.