There is a tradition of worshiping the Katyayani form of Goddess Durga on the sixth day of Navratri. This is the sixth form of Mother Shakti. Goddess Parvati took the form of Maa Katyayani to protect the Gods and Trinity from the demon Mahishasura. Due to killing Mahishasura, the mother is also called Mahishasura Mardini. Maa Katyayani is adored as the goddess of war. This form taken to destroy demons is considered very fierce and fear-inducing.