Once upon a time, there was a saint. His name was Durvasa. He was very short-tempered. Once, all the young gods were playing in the park. Durvasa passed from there but nobody gave respect to him. He became angry and cursed them, saying that they would all become ordinary men. All of the gods lost their powers. They tried really hard to convince Guru Durvasa and requested him a lot.
But Durvasa was furious and walked away from there. The demons came to know that all gods lost their powers. The demons started killing the gods. All gods including god Indra went to seek help from god Vishnu. God Vishnu suggested finding the treasure which was lying at the bottom of the sea, with the help of demons. They got the treasure in which there was gold, diamonds and amrut.
Gods and demons were fighting for amrut. So lord Vishnu took the form of a beautiful girl named Mohini. She said that she would distribute Amrut among the gods and demons. She gave amrut to all the gods. A demon named Rahu stood in the line of gods. He drank a few drops of amrut, and so Vishnu cut Rahu’s head with Sudarshan chakra.