Asura · All traditions · Pan-India
Surasa
The mother of the serpents, sent by the gods to test Hanuman over the ocean; he grows, then shrinks to a thumb and passes in and out of her mouth.
Sources: The Ramayan of Valmiki, tr. Ralph T. H. Griffith: Sundara Kanda and Yuddha Kanda 74 and 101; Sundara Kanda, Wikipedia · see Surasa's web