weapon used by narasimha to slay Hiranyakashipu

Narasimha (the lion avatar of Vishnu) killed the demon Hiranyakashipu using his claws/nails, not any conventional weapon. This was significant because Hiranyakashipu had received a boon that he could not be killed by any weapon (created by humans or gods), neither indoors nor outdoors, neither day nor night, etc. Narashimha bypassed all these conditions by appearing as a half-lion, half-man form and killing him on the threshold (neither indoors nor outdoors) at twilight (neither day nor night) using his claws (not a weapon).