Soon Hiranyakashipu, proud by the boon he got from Brahma, conquered the gods (who are enemies of Daityas) and brought all the worlds under his control. He began to harrass the gods and torture the saints and other devotees of Vishnu.
His eldest son, Prahlada happened to be a great devotee of Vishnu and soon he became a menace to Hiranyakashipu. Prahlada always chanted the names of Vishnu (who is generally treated as an enemy by the Daityas) with devotion. Hiranyakashipu made many efforts to mend his son but could not succeed. At last, he tried to kill Prahlada. But all his attempts went in vain and Prahlada survived due to grace of Vishnu.
Finally, one day Hiranyakashipu summoned Prahlada to his court and asked to accept him (Hiranyakashipu) as the supreme. Prahlada replied that it is Lord Vishnu who is the supreme Lord of the Universe and who pervaded the whole Universe. Angered by this, Hiranyakashipu asked whether he can show Vishnu in the pillar in front of them, if Vishnu was really omnipresent. Prahlada said that since Vishnu resides in each particle of the Universe, he had no doubt that He is very much there in that pillar too. On hearing this, the king became furious and hit the pillar with his weapon. The pillar was broken and instantly from out of it emerged the Vishnu's Narasimha (man-lion) incarnation (nara: man, simha: lion). Narasimha killed Hiranyakashipu using his nails. This way, the boon given by god Brahma was also honoured, as Hiranyakashipu was killed by Vishnu in a man-lion form (which is neither completely human nor completely animal), during twilight time (which is neither day nor night), placing him on Narasimha's thighs (which means neither on earth nor in space) on the threshold of the courthall (which is neithr indoors nor outdoors) using nails (neither animate nor inanimate) as weapons.