Durga Slays Mahishasura
दुर्गा-महिषासुर वध
Quick Answer
The buffalo demon Mahishasura was invincible against all gods. The combined energy of Brahma, Vishnu, Shiva, and all Devas created Goddess Durga, a supreme feminine power. After a fierce nine-day battle, Durga slew Mahishasura, an event celebrated as Navratri and Durga Puja.