Diti had a son named Hiranyakashipu. This demon meditated for eleven thousand years under the water. Throught this period, he did not eat or talk at all. These meditations pleased Brahma and Brahma offered to grant Hiranyakasipu a boon. ―What boon do you wish for?‖ he asked. ―If you are pleased, grant me the following boon,‖ replied the demon. ―I will not be killed by gods, demons, gandharvas, yakshas, rakshasas or snakes. I will not be killed by humans or ghosts. The sages will not be able to curse me. I will not killed by a weapon, a mountain or a tree. I will not be killed during the day or at night. I will not be killed by something that is dry or by something that is wet.‖ This rather strange boon Brahma granted. But the sages, the gods, the gandarvas and the snakes went and complained to Brahma. ―What have you done?‖ they asked. ―This demon is now going to oppress the entire universe.‖ ―Don‘t worry,‖ replied Brahma. ―When the time comes, Vishnu himself will kill Hiranyakashipu.‖
But true to expectations, the demon started to oppress the world. He destroyed the hermitages of the sages and drove the gods out of heaven. All yajnas were stopped. The gods and the sages started praying to Vishnu. Stirred by these prayers, Vishnu adopted the form of a strange being who was half-man and half-lion. Since nara means man and simha means lion, this being was called Narasimha. Narasimha went on a visit to Hiranyakashipu‘s court. Hiranyakashipu had a son named Prahlada and at the sight of Narasimha. Prahlada exclaimed. ―I have a strong suspicion that this being is none other than Vishnu and that we demons will suffer at his hands.‖ Hiranyakashipu asked his soldiers to capture the creature. Or, if that proved to be impossible, to kill it.
But the soldiers could do no such thing; Narasimha killed them all. Hiranyakasipu then himself hurled all sorts of weapons at Narasimha. But great was his bewilderment at finding that all these weapons could do the strange creature no harm. Any weapons could do the strange creature no harm. Any weapon that was hurled was simply swallowed up by Narasimha. The rocks that were flung at him could not even reach him. Narasimha grasped Hiranyakashipu and placed him across his thighs. He then tore apart the demon‘s chest with his claws. Thus, Hiranyakashipu was not killed by a weapon, a mountain or a tree, or by something that was either wet or dry. Vishnu in his Narasimha form was not a god, a demon, a gandharva, a yaksha, a rakshasa, a snake, a human or a ghost. Since the slaying took place in the evening, it was neither night nor day. All the conditions of Brahma‘s boon were met. The entire world rejoiced at the demon-king‘s death.