Ganesha is represented as a short, pot-bellied man with yellow skin, four arms and an elephant's head with only one tusk. In his four hands he customarily holds a shell, a chakra (discus), a mace and a water-lily. His unusual steed is a rat. Ganesha is the second son of Shiva and Parvati. There are many versions of how he was conceived. The most popular version is narrated hereunder.
Shiva and Parvati were leading a quiet life on Mount Kailash, Shiva's habitual abode. In fact, life was too quiet and sedate for Parvati, who had nothing much to do all day as her chosen lord was mostly either immersed in deep meditation or obfuscated by the fumes of ganja (marijuana). For company there was Nandi, Shiva's bull, and his host of ghosts, who are said to inhabit Kailash and give Shiva company, especially when he smokes ganja and wants some song and dance to liven things up a bit. Of course, Parvati was feeling bored and wanted someone she could be more involved with. So she began to call upon Vishnu in prayer to grant her a son. Vishnu soon granted her wish and Parvati gave birth to a beautiful boychild she named Ganesha.
At birth, Ganesha was a perfectly normal boy, with perfect features and body parts, as befits one conceived by a goddess. How he got an elephant's head is another story. Parvati was so pleased at his birth and so proud of his beauty that she invited all the gods and goddesses to come to Kailash and admire him. All the celestial beings came and admired and blessed the boy except Sani (Saturn), Parvati's own brother. This was because Sani had been cursed by his wife and the impact of the curse was that as soon as he looked at someone that person was instantly reduced to ashes.
Naturally, Sani was somewhat reluctant to cause the incineration his own sister's newborn baby but Parvati was feeling so elated that she threw caution to the winds and pleaded with Sani to at least cast his eyes once upon the boy. Sani, perforce, to please his sister, came and, holding his newborn nephew in his arms, hesitatingly gave him one look. That was enough to do the damage. Ganesha's head flew off as soon as his uncle looked at him. Parvati started crying bitterly but Brahma, who was present at this time, comforted her and said that if the head of the first creature that was found would be cut off and transplanted on Ganesha's neck he would live. So Vishnu, who was also present, set off on Garuda in search of any animal he may find. He had to travel all the way down Mount Kailash before, at the foothills, he found an elephant dozing on a riverbank. He immediately cut off the elephant's head and came back.Thus, this is how Ganesha got his pachyderm head. That he is pot-bellied is not a sign of any particular ugliness. The Hindu idea of beauty portrays both men and women with pot-bellies as these are signs of well-fed prosperity.
The elephant's head that Vishnu brought for Ganesha was perfect in all respects, with two tusks, but the pot-bellied god is habitually shown with only one tusk. The story behind how he lost one tusk makes interesting telling.
Shiva was in the habit of intruding upon Parvati while she was bathing. This was rather infrequently, only when that god was not under the influence of ganja. Anyway, Parvati found this habit of her forgetful lord rather annoying. One day, when the beautiful goddess was about to get a bath in the water of a pool inside a cave, she took the precaution of positioning Ganesha, her favorite son, at the entrance of the cave. She strictly instructed him not to let anybody in while she was inside. So it was that Ganesha stood guard while his mother bathed inside till he spied his father ambling towards the cave. Coming up to the cave entrance, Shiva demanded admittance but Ganesha stood his ground bravely and refused to allow his father in.
Shiva was astounded at this. He protested that no-one had the right to keep him away from his rightful wife but Ganesha did not budge from his post saying that he would not disobey his mother's instructions. Shiva, hot-tempered as he was, flew into a terrific rage and attacked his own son. Ganesha parried his father's attack and both fought for quite some time. All this while Parvati unwittingly went on bathing inside, unaware that her ablutionary precaution was causing unforeseen dissension within her family. Son and father fought till, at last, Shiva hurled his trident, his supreme weapon, at his son. Ganesha would not parry this as, to do so, would be to show great disrespect for his father. So he took the blow from the trident on one tusk, which broke off. At this point in time, Parvati emerged from her bath and, perceiving what has been going on, hastened to bring amity back to her family. Since then Ganesha, benevolent initiator, has had one tusk.
There is another interesting story pertaining to Ganesha and his brother Karttikeya. Both wanted to marry Buddhi and Siddhi. So, at last, they decided between themselves that the first of them to circumnavigate the earth entirely would get their hands in marriage. Karttikeya set out on foot to circle the earth but Ganesha sat at home studying the scriptures. After long years of travel Karttikeya returned, only to find that his brother was already married to the two ladies. Ganesha had stayed at home and studied the scriptures and, through his studies, had gone round the earth in much lesser time than his more physical and less astute brother, Karttikeya, had on foot.