Narada tells Yudhishthira the story of Sunda and Upasunda

Narada addressed Yudhishthira and his brothers. He told them to listen to an ancient account, exactly as it happened. In the lineage of the great asura Hiranyakashipu, there was a powerful lord of the daityas (demons) named Nikumba. He had two sons of immense and terrible prowess. They were inseparable. They never ate unless together, never went anywhere without the other. They acted only to please each other, spoke only pleasant words. In behaviour and conduct, they were like one soul divided into two bodies. With identical action and inclination, they grew up valorous and adopted a single resolution: to conquer the three worlds. After consecration, they went to the Vindhya mountains to perform terrible austerities. They exhausted themselves with hunger and thirst. Their hair matted, dressed in tree bark, they continued their penance until they acquired power. They covered their limbs with filth, lived on air alone, and offered their own flesh into the sacred fire. They stood on the tips of their toes, arms raised, eyes unblinking, observing their vows for a long, long time. The power generated by the length of their austerities grew so intense that the Vindhya mountains themselves began to belch out smoke. The gods saw this terrible power and were frightened. They created various obstacles to break the brothers' vows. They sent temptations of jewels and beautiful women. The two stood firm. Then the gods used the power of Maya (illusion) on the great-souled brothers. An illusion appeared where their sisters, mothers, wives, and relatives, trembling and frightened, were chased by a rakshasa (demon) with a spear. Their hair and ornaments were dishevelled, their garments loose. The women seemed to run towards the brothers, crying, "Save us!" Even this horrific vision could not break the vows of those who were great in their vows. When they showed no shock or grief, the women and the demon vanished. Then Brahma, the grandfather of all worlds, appeared before the great asuras. Pleased, he asked them to seek a boon. Seeing the god, Sunda and Upasunda stood before him with joined hands. Together they spoke: "O grandfather! If you are pleased with our austerities, grant us the knowledge of delusion and the knowledge of all weapons. May we be strong and have the power to change our form at will. If you are pleased, may we be immortal." Brahma replied, "Except for immortality, everything else will be as you wish. Choose a means of death that will make you the equal of the immortals. You performed these austerities with the objective of conquering the three worlds. For that reason, I cannot grant the boon you desire." Sunda and Upasunda said, "O grandfather! Then let us fear no being, anything mobile or immobile, any object in the three worlds—other than each other." The grandfather said, "I grant this boon as you have wished it. Your deaths will occur as you have indicated." Having granted the boon, Brahma asked them to refrain from austerities and returned to his world. Having obtained these boons, the two lords of the daityas, who could no longer be slain by anyone in the worlds, returned home. Their well-wishers, seeing them successful, were overjoyed. The great asuras cut off their matted locks. They wore crowns, expensive ornaments, and unblemished garments. Though it was not the season, they observed the koumudi festival. The lords of the daityas and their well-wishers happily enjoyed the festivities. In house after house echoed the words: "eat," "feed," "pleasure," "sing," "drink," and "give." There was great drinking. A roar arose from the clapping of hands. The entire daitya city went wild with joy. As the daityas, who could assume any form at will, sported in varied amusements, many years passed—but it seemed like a single day.