Narasimha, half man, half lion, is one of the ten incarnations of the god Vishnu and worshipped as the Great Protector.
Vishnu killed the demon Hiryanakashyap so his brother, Hiryanakashyipu wanted revenge on Vishnu. Hiranyakashyipu had been given a boon by Brahma that he would not be killed by human, god or animal, neither in the day nor at night, neither inside the house nor outside, neither on earth nor in space, neither by animate nor inanimate weapon.
As Narasimha was not human or god or animal - he is Vishnu incarnate but part-human, part-animal - he came upon Hiranyakashyipu at twilight (when it was neither day nor night) on the threshold of a courtyard (neither indoors nor out), and put the demon on his thighs (neither earth nor space). Using his sharp fingernails (neither animate nor inanimate) as weapons, he disemboweled and killed the demon.