Guru Sandipani was a very learned teacher and he was from the city of Ujjain. He was chosen to be the teacher of Krishna, because the man was a brilliant teacher and well-versed in all the arts.

And this time, Guru Sandipani had found brilliant students. It was said that Krishna, Balarama and Sudama, a friend of the two brothers, learnt every lesson that the teacher taught them – though they were taught only once. They were that good in their studies.

They were so quick and their grasp was so fast that within a very short time, all the three boys finished their education.

Immediately, Krishna and Balarama went to the teacher and as a mark of the end of their education, they requested their teacher to ask anything from them as a mark of Gurudakshina. (Gurudakshina is made of two words - "Guru" meaning teacher and "Dakshina" meaning fees. So literally translated, Gurudakshina means the fees which is offered to the teacher at the end of the education. It is said that the teachers can ask anything from their students, which the students would be bound to fulfil.)

Hearing the words of the brothers, however, the Guru's face drooped in unhappiness.

"What is it?" Krishna asked looking worried.

The teacher was really silent for a long time, but both the brothers were patient. Finally, the Guru sighed as he looked at the two brothers. The two brothers were shocked to see a single tear flowing down the eye of the teacher.

"What is it?" Balarama asked even more worried.

"I have..." The Guru's words chocked as he was unable to talk. Then he pulled himself as he studied the two boys. "I had a son."

The brothers were shocked as the Guru nodded unhappily. "My son drowned in the ocean at Prabhasa." Guru Sandipani looked at the dark Krishna and nodded unhappily. "I know what I want is not possible."

Krishna smiled as he looked at his teacher. "I promised to give you anything that you wanted as Guru Dakshina. You want your son. I shall bring him back."

Guru Sandipani, did not know what to say as he was looking shocked at the two brothers.

But then the two brothers did not look back.

They started for Prabhasa.

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Krishna asked around the people in Prabhasa and there he realized that many years back there lived an asura called "Panchajanya" - meaning the conch demon. (Some versions call the conch demon as Shankhasura.)

This demon moved all over the ocean hidden inside a conch.

As Krishna asked around, he realized that Panchajanya had taken the son of Guru Sandipani.

Krishna did not waste anymore time and it is said that he waded into the deeper depths of the ocean and there after searching he found the conch demon.

A terrible battle ensued there between Krishna and the demon. But Krishna was naturally stronger.

He killed the demon.

(Some Puranas even say that Krishna could not find the boy anywhere even after defeating Panchajanya.

That was when Krishna had finally realized that the boy was dead.

Not admitting defeat, Krishna and Balarama visited the realms of Lord Yama – the God of Death.

It is also said that the two brothers were happily welcomed by Yama. And when the two brothers expressed their desire to get back the teacher's son, Yama agreed and handed over the boy back to Krishna.)

The two brothers brought the boy back and fulfilled their Gurudakshina.

Guru Sandipani was so thrilled on getting his son back and words utterly failed him.

When the guru had recovered, he looked at the conch in which the Panchajanya had lived and handed it over to Krishna. It is said that the guru blessed Krishna that whenever Krishna blew the conch it would spell doom for his next opponent.

This conch is extremely important, because many years later, it is believed that the great war of Kurukshetra commenced only after Krishna blew the Panchajanya.