KARKOṬAKA A terrible serpent.
1)
Birth. This serpent was born to Kaśyapa by his wife Kadrū.
2)
The curse. Once Karkoṭaka cheated the sage Nārada. The angry sage cursed him and said that he would have to remain without the power of movements in the forest till Nala came to rescue him. From that day Karkoṭaka lived in that forest, awaiting the arrival of Nala.
3)
Nala and Karkoṭaka. Once a wild fire spread all over the forest. Karkoṭaka whose power of movement was destroyed by Nārada's curse, cried aloud, calling upon Nala to come and save him. It was at this time that Nala arrived at the spot after leaving Damayantī in the forest. Nala came to him, on hearing his cries. The serpent informed Nala about the story of Nārada's curse and reducing himself to the size of a thumb sat on the ground. Nala removed him to a safe spot away from the fire. The serpent asked Nala to walk a few steps counting his footsteps. Nala did so and at the tenth step, Karkoṭaka stung him and his whole body was turned blue. Suddenly Karkoṭaka assumed his own original shape and spoke to Nala as follows:--“I have changed your appearance so that people may not be able to recognize you. Kali who is troubling you, still lives within you. It is he who is affected by my poison. You need not fear danger from poison any more. You will never be defeated in battle. Go and engage yourself as the charioteer of Ṛtuparṇa, King of Ayodhyā. You will teach him Aśvahṛdaya mantra. In return for it he will teach you Akṣahṛdaya mantra. Here are two garments which I give you. If you put them on, you will be restored to your own shape. May you be blessed again with a happy family life.” After saying this, Karkoṭaka vanished.
[M.B. Vana Parva, Chapter 66] .