Many snakes died in the snake Yajna of Janmejaya. Very few were left alive. This pained Vasuki, the King of the snakes a lot. He went to his sister Jaratkaru and said, "Sister, I feel as if I am burning, I cannot understand what is to become of us. I am feeling faint and my resistance to the fire of the Yajna is weakening. I am being pulled towards the fire and I feel as if very soon I shall be drawn into the fire as well. I had married you to Rishi Jaratkaru in anticipation of this day. Now, you are the only one who can save us. According to Brahma, your son Aasteek will be able to stop this Yajna. I know that he is still a boy, but he is a great scholar of the Vedas and is loved by all his elders. You ask him to save our lives now or the snakes will disappear from earth." Listening to her brother, Jaratkaru went to her son and requested him to save the lives of the snakes. Aasteek went to Vasuki and said, "O, King of the snakes, do not fear and rest assured. I shall get you rid of the curse. I have never spoken a lie even in jest. I shall go to King Janmejaya and impress him with my knowledge and request him to stop the yajna. Uncle please trust me."

Thus assuring Vasuki, Aasteek left for the venue of the Yajna. When he reached there he saw all the eminent people sitting there. But he was not allowed to go inside by the sentries. Then he started to sing hymns in praise of the Yajna so that he would be allowed inside.

On listening to the sweet voice of Aasteek, Janmejaya gave him permission to attend the Yajna and called him inside the premises. Once inside, Aasteek sang praises of all those who were present there and this pleased the congregation. Janmejaya thought that he should grant the boy a wish as he was mature for his years and a great scholar. He asked the wise sages present there what he should do. They replied that as the boy was a brahmin and a scholar at that, he was venerable. Janmejaya then requested to all those who were present there to ensure that his Yajna was successful and that soon Takshak (the snake who had bitten his father, Parikshit), would fall into the fires of the Yajna and die. The wise men at the Yajna told Janmejaya that Takshak had gone to Indra (the god of Thunder and Lightening) and Indra had promised full protection to Takshak. Hearing this Janmejaya was saddened and he requested the sages and priests to chant such a mantra that even Indra would be powerless before it and would fall into the fire with Takshak. On hearing this, the priests did as they were told and soon Takshak along with Indra was pulled towards the fire. When Indra saw the Yajna he was perturbed and and left Takshak to fend for himself. Takshak started to be pulled towards the fire with each passing minute.

Now that Janmejaya was assured that his enemy would die, he turned to Aasteek and requested him to ask for anything that he wished for. Aasteek, seeing that Takshak would soon fall into the fire, took advantage of the situation and asked Janmejaya to stop the Snake Yajna so that the snakes who were left could survive. This saddened Janmejaya and he requested him to ask for anything other than this. Aasteek was not one to give up easily, he asked Janmejaya to stop the Yajna and also reminded him that he could not refuse what he had promised. He said that he was asking for this because he had to save his mother's clan.

Janmejaya had to relent and stooped the Yajna and had the fires put out. Meanwhile Aasteek stopped the rapid descent of Takshak towards the fire by saying, "Stop! Stop! Stop!" Takshak was relieved andd grateful that his life was saved and he thanked Aasteek.

Everyone expressed their delight at the stopping of the Yajna. Janmejaya requested Aasteek to attend his Aswamedh Yajna (the Yajna which is performed to conquer the whole world) and also offered him gifts.

Aasteek then left to go to Vasuki, his Uncle and Jaratkaru, his mother and narrated the whole incident to them.

The court of Vasuki, the king of the snakes was full of the snakes who had survived the ordeal of the Yajna. They collectively blessed Aasteek and asked him to ask them for a boon. Aasteek wished that anyone who chanted the three mantras given by him at least once a day, should be spared death by a snake bite. He then chanted the three Mantras called Asit, Aartiman and Suneeth. The sankes granted Aasteek his wish and it is believed that if one chants one of these mantras even once a day, he will have nothing to fear from the snakes.

The Mantras are as follows:

"Yo Jaratkaruna Jato Jaratkarau Mahayashah;
Aasteekah Sarpsatray vah Pannagaan Yobhyarakshat;
Tam Samarantam mahabhaga na Mam Hinsitumarhatha."

"A great sage called Aasteek was born to Saint Jaratkaru and the snake woman, Jaratkaru. Aasteek saved the snakes from the Snake Yajna. So all of you holy and lucky snakes, I am remembering him. Please do not bite me."

"Sarpapsarpa Bhadram Te Gachcha Sarpa Mahavisha;
Janmejasya Yajnante Aasteekvachanam Smara."

"Hey, all ye holy and poisonous snakes! Please go away. May you be blessed. Remember all that Aasteek said at the end of the Snake Yajna of Janmejaya and go away now."

"Aasteekasya Vachah Shrutva Yah Sarpo na Nivartate;
shatadha bhidyate Murdhina Shinshavrikshaphalam Yatha."

"The snakes who do not return even after hearing the words of Aasteek, their hoods will be split into hundreds of pieces like the fruit of the Shisham tree"