"Rikki-Tikki-Tavi" is a short story in the 1894 anthology The Jungle Book by Rudyard Kipling about the adventures of a valiant young Indian mongoose. The story follows the experiences of a mongoose named Rikki-Tikki-Tavi (after his chattering vocalizations) after he becomes the pet of a British family residing in India as protection against cobras. He becomes friendly with some of the other creatures inhabiting the garden and is warned of the cobras Nag and Nagaina, who are angered by the family's presence on their territory.
Accordingly, Nag enters the house's bathroom before dawn to kill the humans and make Rikki leave, so that their babies will grow up in a safe place. Rikki attacks Nag from behind him in the bathroom; the ensuing struggle awakens the family, and Rikki kills Nag with one bite in the back of Nag's neck.
The grieving Nagaina attempts revenge against the humans, cornering them as they have breakfast on an outdoor veranda. She is distracted by a female tailor bird, while Rikki destroys the cobra's unhatched brood of eggs, except for one. He carries it to where Nagaina is threatening to bite little Teddy while his parents watch helplessly.
Nagaina recovers her egg but is pursued by Rikki away from the house to the cobra's underground nest, where an unseen final battle takes place. Rikki emerges triumphant from the hole, declaring Nagaina dead. His subsequent role is to protect the family by keeping the garden free from any future intrusion of snakes.