Once upon a time, there was a big king who lived by the name of Bhasmasura. He was strong and powerful by birth, yet he wanted to grow stronger and was always greedy to gain more power. Once when walking in the forest, he was thinking to himself on how he could become more powerful, when he came across sage Narada. So, he decided to go and ask him for guidance.
Bhasmasura then went and approached sage Narada, seeking ways to get more powerful. To this, sage Narada said that he could become more powerful by worshipping Lord Shiva. Bhasmasura then thanked him and immediately commenced his penance towards Lord Shiva. Many years passed by, but Bhasmasura remained dedicated in his penance and he was so motionless that ants built an entire anthill around his huge body. Finally, after many decades, Lord Shiva appeared and removed the anthill around Bhasmasura. He then granted Bhasmasura a boon. Bhasmasura was very delighted and so he asked for immortality.
Now, no god was allowed to give immortality as a boon, because it was against the laws of nature and so Lord Shiva refused and told Bhasmasura to ask for another boon. Bhasmasura then thought and asked Lord Shiva for a boon, granting his right hand the power to turn anyone to ash, if he touched their head. Lord Shiva without thinking twice, granted the boon and soon after this Bhasmasura began to laugh loudly.
Bhasmasura laughed like a crazy man and with this new boon, he proclaimed that he was mightier than Lord Shiva and he threatened to turn Lord Shiva to ash. Lord Shiva was shocked and started to run. Bhasmasura chased him here and there, until Lord Shiva went out of sight. Lord Shiva hid behind a tree and sought help from Lord Vishnu.
Bhasmasura was still searching for Lord Shiva when he suddenly saw a beautiful lady and once he saw her, he instantly forgot about Lord Shiva. Bhasmasura had fallen in love with this beautiful lady and approaching her, he asked her name. The lady answered him, saying that her name was Mohini. Bhasmasura, without waiting, asked if she was willing to marry him. Mohini chuckled and said that she would marry a man who only knew how to dance. Bhasmasura was shocked to hear this as he did not know how to dance and said the same to Mohini. She replied calmly saying that she would teach him and after that he could marry her. Bhasmasura was happy to hear this and soon Mohini began to teach Bhasmasura on how to dance.
They danced day and night and this went on for many days. Lord Shiva was watching all this from the shadows and was wondering as to what was going on. Meanwhile, the difficulty of the dance progressed as Bhasmasura was gradually improving in his performance. Soon, Mohini was making complex steps and one of them included keeping the right hand on the head. As Bhasmasura was immersed in the dance of Mohini, he imitated all steps blindly and copied this too. As soon as Bhasmasura kept his own right hand on his head, he turned to ash and died instantly.
On seeing this, Lord Shiva emerged from the shadows and he thanked Mohini for defeating the demon. But alas! Mohini was none other than Lord Vishnu himself and he smiled happily at Lord Shiva and said that he was happy to help him anytime.