As the Udyoga Parva tells it
Mahabharata, Udyoga Parva 11 to 17 · 3 min read
Indra was gone. After the killing of Vritra he had fled to the edge of the worlds and hidden in the waters, and heaven had no king. The rains failed. The gods and the sages looked about for someone to sit on the empty throne, and they chose a man, King Nahusha, who was famous for his goodness.
"I am too weak for this," Nahusha told them. "It is Indra who has the strength."
"Then take ours," they said. "Whoever stands within your sight, god or demon or sage, you shall draw his power into yourself."
So Nahusha was crowned, and for a while he ruled well. Then the gardens, the music and the gift of that gaze began to change him. One day he saw Shachi, Indra's queen.
"I am the king of the gods now," he said. "Why does Indra's queen not wait on me? Let her come to my house."
Shachi ran to Brihaspati, the teacher of the gods.
"I will not give up anyone who has come to me for shelter," Brihaspati said. "But ask him for time. Time brings many things."
She went to Nahusha trembling and asked for time, to learn what had become of her husband. He was pleased and let her go.
That night Shachi prayed to the goddess Night, and by her own truthfulness she called up Divination, who came as a young woman and said, "Follow me."
They crossed the gardens of heaven and the Himalaya and came to an island in a northern sea. On it lay a lake covered with lotuses of five colours, and in the middle stood one tall white lotus. Divination went into its stalk, and Shachi made herself small and went in after her. There, among the fibres, lay Indra, shrunk almost to nothing.
"Why have you come?" he asked. "How did you find me?"
She told him everything. "Rise," she said. "Take up your strength and kill him."
"This is not the time for strength," said Indra. "He is stronger than I am. The sages have made him so. Go back and tell him this: come to me in a carriage that no god has ever had, a litter carried by the great sages. Say that then you will be his."
Shachi went back and said it. Nahusha laughed with pleasure.
"A carriage nobody has heard of! Only a mighty man makes sages carry him. It shall be done."
He put the seven sages and others under the poles of his litter. When Brihaspati heard, he said quietly, "Then he is finished already."
Brihaspati lit a fire and sent Agni to look for Indra. Agni searched earth and sky in the blink of an eye and came back.
"He must be in the waters," said Agni, "and I cannot go into water. It is the end of me."
Brihaspati praised him until he found the courage. Agni went through every sea and pond, and found the lake, and the lotus, and Indra in its stalk. The gods went there and sang Indra's old deeds to him, and as they sang he grew, little by little, to his own size.
They were still planning how to face Nahusha when the sage Agastya arrived.
"It is over," Agastya said. "We were carrying him, and we were tired. We asked him whether certain hymns of the Veda were true. He said they were not. Then he put his foot on my head. So I said to him: fall. Be a serpent on the earth for ten thousand years."
Indra returned to heaven, and Shachi with him.
As the serpent tells it
Mahabharata, Vana Parva 178 to 181 · the Himalayan forest · 1 min read
Ages later, when the five Pandava brothers were living in exile in the forest, Bhima went hunting alone in the Himalaya. In a mountain cave an enormous serpent caught him. Bhima had the strength of many elephants, and he could not move a finger.
His eldest brother Yudhishthira followed his tracks and found him wrapped in the coils.
"Who are you?" Yudhishthira asked. "Let my brother go. I will give you other food."
"I am Nahusha," said the serpent. "I am your own ancestor. Once I was king of heaven. Answer my questions, and your brother goes free."
He asked who should truly be called a Brahmin. Yudhishthira said it was the one in whom truth, giving, forgiveness and kindness were found, and that birth alone settled nothing. The serpent asked more, and was content with every answer.
Then Yudhishthira asked a question of his own.
"You knew all this. You did great deeds. How could folly master you?"
"Good fortune makes even wise men drunk," said the serpent. "I rode through heaven in my chariot and thought of nothing but myself. I took tribute from sages and gods. Whoever I looked at lost his strength to me. A thousand sages drew my chariot. One day Agastya was among them, and my foot touched him. He said: be ruined, become a snake. I fell head first from the chariot, and as I fell I saw my own body change."
"Did you ask his pardon?"
"While I was still falling. He took pity and said that King Yudhishthira would free me one day. Now you have talked with me, and it is done."
He let Bhima go. The serpent's body dropped from him, and Nahusha went back to heaven in his own shape.