In Vaishnavism, Hiranyakashipu is the great king of demons, and he had been granted a boon by Brahma, which made it almost impossible for him to be killed. The boon was due to his long penance, after which he had demanded that he not be killed "during day or night; inside the home or outside, not on earth or in the sky; neither by a man nor an animal; neither by astra nor by shastra". Consequently, he grew arrogant and attacked the Heavens and the Earth. He demanded that people stop worshipping Gods and start praising him.
According to this belief, Hiranyakashipu's own son, Prahlada, was a devotee of Lord Vishnu. In spite of several threats from Hiranyakashipu, Prahlada continued offering prayers to Lord Vishnu. He was poisoned by Hiranyakashipu, but the poison turned to nectar in his mouth. He was ordered to be trampled by elephants yet remained unharmed. He was put in a room with hungry, poisonous snakes and survived. All of Hiranyakashipu's attempts to kill his son failed. Finally, he ordered young Prahlada to sit on a pyre on the lap of his demoness sister, Holika, who could not die because she also had a boon. And a boon which would prevent fire from burning her. Prahlada readily accepted his father's orders, and prayed to Vishnu to keep him safe. When the fire started, everyone watched in amazement as Holika burnt to death, while Prahlada survived unharmed, the burning of Holika is celebrated as Holi