The name Murari (Mura – the name of a demon; Ari – enemy) is attributed to Lord Krishna since he once vanquished the demon named Mura. There is an interesting story behind how Lord Krishna put an end to the arrogant Mura in a clever way.
Mura was the son of Sage Kashyap. Having realized that the demons are always targeted and killed by the gods, Mura undertook a severe penance to please Brahma. After several years of his rigorous austerity, Brahma appeared in front of him and asked what boons he wished for. Mura opted for immortality, which was denied since it was practically not possible to grant it to any mortal being. Following that, Mura asked that anyone touches him during a battle must at once die. This wish was however granted by the merciful Lord. With his head bloating up due to the special power he had got, Mura toured the three worlds and brought them under his control.
The boon became the bane
Fearing Mura, Indra – the king of gods fled to an unknown place. When Mura played his pranks to Lord Yama, Lord Yama reported the matter to Vishnu who then summoned Mura to his presence. Mura eagerly visited Vishnu in the pursuit of inviting him for a combat and killing him with the rare boon he had received. Lord Vishnu smiled at him and said, “Oh the most powerful demon, I am ready to fight with you, but I see your heart throbbing in fear. I do not wish to fight with a person who is terrified”. Mura said he was never afraid to fight with Vishnu. Lord Vishnu then directed him to check his heart beat by placing his hands on the chest. Mura complied with the directions like a fool only to be burnt alive due to his own boon. Yes the boon that whoever touches him in a battle would be killed worked against his own self now when he touched his chest to check the heartbeat.
Having vanquished the demon Mura, Krishna came to be called as Murari.