Mount Indrakila, in the mighty Himalayas, was a tranquil abode to many sages who conducted prayers and performed severe penances the gods.
One day, the sages saw a stranger walking towards their abode. They noticed that even though the stranger was wearing sage’s saffron clothes, he looked nothing like one. He was tall, well-built and was carrying weapons. On seeing the golden hilt of the sword, they recognized the stranger to be the Pandava prince, Arjun.
One of the sages whispered, “The Pandavas were banished from their kingdom, after losing a game of dice with Duryodhan. But what is Prince Arjun doing here?”
Arjun walked silently to a secluded spot and sat down to make a Shiva linga from mud to perform severe penances to Lord Shiva. He didn’t stop his penance for anything. After a few months, the earth around him was unable to bear the heat of his penance and started emanating black smoke around him. The smoke spread throughout Mount Indrakila, and the sages fled to Mount Kailash.
They approached Lord Shiva, who was sitting beside Goddess Parvati, and pleaded to intervene. Lord Shiva smiled and replied, “Please go back to Mount Indrakila. I will resolve your problem.”
After the sages left, Lord Shiva could see doubts clouding the Goddess Parvati’s’ face. He asked her, “What is troubling you? Don’t hesitate to ask.”
Goddess Parvati asked him, “Why is Arjun performing such severe penance?” He replied, “Because he wants blessed weapons for the impending war.” She still had her doubts and asked, “Do you believe that he will use the weapons wisely?” “Well, we will have to find that out,” he replied.
Lord Shiva told her about his plan to test Arjun. He disguised himself as a Kirata Chief (Kirata is a clan of mountain dwellers), and asked Goddess Parvati and some of his followers to dress up as Kirata women.
When they were nearing Mount Indrakila, Goddess Parvati pointed at a wild boar at some distance and said, “That does not look like an ordinary boar.” Lord Shiva looked at it and said, “You are right. That looks like the Asura, Muka. He seems to heading towards the sages to disrupt their prayers.”
Lord Shiva took an aim at the demon with his bow and arrow, but the demon sensed the presence of Lord Shiva and fled. Lord Shiva chased him to the sage’s abode, and as soon as the sages saw the boar charging towards them they started running, screaming for help.
Muka ran to the spot where Arjun was performing his penance. Arjun sensed the boar’s presence and opened his eyes. He took up his bow and arrow to kill it. When Lord Shiva also reached the spot, he said, “Stop! That is my prey. You cannot kill it.” Arjun was not able to recognize Lord Shiva in disguise and replied, “I will not put down my bow. If you are a true hunter take your aim and kill it.”
Both shot their arrows at the boar. As soon as arrows pierced, the animal resumed its original demonic self and died. The Kirata women watching the demon fall down to his death, started dancing and celebrating.
But it was not clear who had struck the boar first, and neither party was ready to concede defeat. The Kirata women argued, “He is lying, O chief! You killed the boar before him.” Arjun did not like to be insulted so challenged the Kirata chief for a duel.
Soon, arrows started flying between Arjun and Lord Shiva. They hurled their best arrows at each other, but neither of them was hurt. Suddenly, Arjun realized that his quiver of arrows was empty. Lord Shiva smiled at him and offered, “You can borrow some arrows from me.” Hearing this, the Kirata women started mocking Arjun.
Arjun angrily threw his bow at the hunter, who caught it, tore the string and flung it away. Not able to control his anger, Arjun took his sword, and charged him with all his might. The sword dissolved into flowers as it struck the hunter. Everyone was surprised to see the miracle, and the Kirata women cheered their chief.
Refusing to lose, Arjun picked up a tree with his bare hands and hurled it at the hunter, who dodged it easily. Unable to concede defeat, he decided to pray to Lord Shiva for strength. He sat down in front of the linga and started chanting “Om Namaah Shivaya” and placed a garland on the linga.
Soon, he felt strength infuse his body. Happy that his prayers had been heard, he turned towards the Kirata hunter and said, “Lord Shiva had blessed me with strength. Come, let’s see who wins now.” But then, he saw the linga was placed next to where the hunter was standing.
When Arjun realized that the Kirata chief was none other than Lord Shiva in disguise, he bowed in front of him and said, “Please pardon me, Lord. I didn’t know who I was fighting.” Lord Shiva replied, “O valiant prince, you have appeased me with your devotion. I grant you this Pashupata, the blessed arrow to aid you in your war.”
Years later, during Mahabharata, Arjun used the Pashupata arrow to defeat Karna.