Demon Mahishasura of Chamundi Mysore

Thanks to the Buffalo Demon Mahishasura Statue

According to Hindu mythology, Mahishasura was a combination of both an Asura and a Mahisha (Water buffalo) with trident. He intended to annihilate all the Deva's since they were the arch-enemies of Asuras. The legend of Mahishasura is important in Hindu mythology since the goddess Durga was incarnated in order to slay him. Therefore, his story is an important part of Shaktiism which venerates the goddess Durga.

The popular legend is that Mysuru gets its name from Goddess Durga, Mahishasura Mardini. It is believed that the people of this region were saved from the Buffalo Demon Mahishasura who had come from bottom South and occupied the land. This is when people prayed to Goddess Durga for help and she descended during a sacred period which is now called Navratri and Dushera. Thus, the Nine days battle took place on the Chamundi Hills where he was slayed at last. Hence, the Dusshera festival is the biggest festival, the State Festival in Kannada and is famously known as Mysore Dasara.

Rambha, the king ofAsuras, was enticed with the beauty of a she-buffalo and eventually married her. The child who was born from this bestial union was named Mahishasura, because he was half-buffalo and half-human (Mahisha literally means buffalo). As an Asura, Mahishasura wanted to wage war against the Devas, who were the Asuras' arch-enemies. To make himself invincible Mahishasura performed austerities to Brahma  and asked to be granted immortality. Brahma refused him the boon of immortality and instead gave him a boon such that his death would happen only at the hands of a woman. Mahishasura imagined that this was the equivalent of immortality, since he believed it was impossible for a woman to slay a person of his strength. Emboldened by this belief, he started a war with the Devas. In the battle that ensued, the Devas, led by Indra, were defeated. At this point the Devas approached the trinity of Shiva, Brahma, Vishnu to seek help. The three great gods combined their divine energies and created a woman. The Goddess thus created was Durga Durga led a battle against Mahishasura and killed him, thus fulfilling the prophecy that he would meet his death at the hands of a woman.

Durga slaying Mahishasura is a prominent theme which was sculpted in various caves and temples across India. 

Some of the prominent representations are seen at the Mahishasuramardini caves in Mahabalipuram, the  Ellora caves, in the entrance of Rani Ki Vav Hysaleeswara Temple in Halebidu and many more temples across India.