Birth of Mayuresvara
The Puranic texts mention the legends related to the birth and life of the Mayureshwara avatar. Once all the gods were conquered by the demon Sindhu. Thus Lord Shiva along with Goddess Parvati and seven crores of ganas (divine army of Shiva) moved to the Trisandhya Kshetra. Gautama Maharishi and other sages were already present there who worshipped Shiva and His consort. Later Shiva resided in an abode which was constructed by the sages at the bank of the lake. Once Parvati left her abode and went to a mountain peak to perform deep meditation. She continued Her tapas and prayed to the Supreme Lord for twelve years without consuming air. Eventually the Supreme Lord appeared before Parvati.
The Lord had ten arms and was embellished with kundalas and kirita. His forehead was adorned with the tilak of kasturi and the crescent moon was placed over his head. The face was of Lord Narayana (Vishnu), the left face was of Lord Brahma and the right face was of Lord Shiva. The Supreme Lord had a fair complexion and was seated in the padmasana posture over the divine serpent Sesha Naga. He was very pleased with the devotion of Parvati and requested Her to ask for a boon. Parvati only desired to worship the Lord and please Him. So She wished to have him as Her son. The Lord granted Her the boon and disappeared.
Later Shiva told Parvati that Lord Ganesha would be born to them as their son who would eliminate all evil. Parvati worshipped Ganesha in sixteen forms on the fourth day of Bhadrapada on Simha lagna when the five noble planets were in a single house. Suddenly a divine figure appeared before her. He had innumerous mouths, infinite eyes, noses, ears, feet and hands. He declared himself as Lord Ganesha who was adored by Goddess Parvati. She requested the Lord to leave this mammoth form and appear in a childlike form. All of a sudden an infant with three eyes and six arms appeared there. His face and nose was very beautiful and had a wide chest. His feet had the marks of a lotus, a flag and ankusa. His body had the splendour of crores of suns. Thus Lord Ganesha adopted the form of Mayuresvara and became the son of Shiva and Parvati.
There are several legends related to the Lord Mayuresvara form of Ganesha mentioned in the Ganesha Purana. He ultimately killed the demon Sindhu and saved all the gods and sages.