Sesha Naga is the thousand headed snake on whom Hindu God Vishnu reclines. Shesha Naag floats on the cosmic ocean and Sri Hari Vishnu reclines on the bed created by coiling of the body of Sesha. As per Hindu tradition, when the dissolution of the world takes place, Sesha remains. He witnesses the destruction of the entire universe. As He is eternal, he is known as Ananta Sesha.
Another belief in Hindu tradition is that the earth rests on the head of Ananta Shesha. Thus in Hindu folktales it was narrated that earthquakes happened when Shesha moved his head.
Legend has it that Sesha appeared as Lakshman, when Vishnu took the incarnation of Rama. He later appeared as Balram when Vishnu took the incarnation of