Avatar 4 :

Narasimha is half-man, half-lion (“Nara” for “Man” and “Simha” for “Lion”) . Vishnu came in this form to kill the king of the demons, Hiranyakasipu, the older brother of Hiranyaksa. Hiranyakasipu had also got Brahma to grant him immunity against human, beast and god. Hiranyakasipu received the blessing that he could not be killed by man, beast, demigod, or any kind of weapon or hands. He would also not die in the air, in water, or on the ground, nor be killed either inside or outside, neither during the day nor at night.
Prahlad was the son of Hiranyakasipu, and because the boy was a great devotee of Vishnu, his father tortured him. To save his devotee Prahlad, Narasimha appeared to kill Hiranyakasipu.
He killed him on his lap, so that he was killed neither on land nor in water. He was killed in the doorway of the assembly hall, which was neither inside nor outside. He was torn apart by Narasimha’s nails, which was neither a weapon nor hands. He was killed at dusk, which was neither day nor night.