Ananta

Ananta: a cosmic snake

 Ananta literally means “without end,” “infinite.” It was a descriptive term used
of Vishnu and other gods. It was also used as a name of Vishnu’s serpent.
Ananta was the giant serpent that floated upon the Milky Ocean and formed
the bed for Vishnu as he slept during the involution of the universe (pralaya).
Ananta (also known as S´esha) was the son of Kas´yâpa, the grandfather of all
beings, by his wife Kadrû. Other serpents, such as Vâsuki, Takshâka, and
Karkkotaka, were his brothers. Bala-Râma was a partial incarnation of Ananta.

- George M Williams, Handbook of Hindu Mythology (2001)