In Hinduism, Vamana is the fifth avatar of Vishnu, a dwarf. He tricked the Devas' enemy Bali into giving up all of the heavens and earth. Vamana asked for a piece of land only three paces wide and Bali agreed; Vamana grew in size and stepped across the earth in one step, the heavens in the second and elected not to claim the underworld, leaving that for Bali to keep. However, Bali did not wish to leave his promise unfulfilled. Therefore, Vamana agreed to use the third step for Bali's own head. Bali was made immortal, and is said to be in the underworld to this day.
Bali is supposed to return every year to the land of his people, to ensure that they are prosperous. This is celebrated as the Onam festival in Kerala, where he is called Maveli or Mahabali.