Three ways Kipling foreshadows the life-or-death struggle Rikki finds himself in with the snakes are through the conversations of Teddy's father and mother, Chuchundra and Rikki, and Nag and Nagaina. These conversations reveal clues about what lies ahead for Rikki, and each one builds upon the other and increases suspense.
First, when Teddy's mother suggests Rikki may bite her son, his father says Rikki would be better than a bloodhound "if a snake came into the nursery now." The mother's unwillingness to "think of anything so awful" lays the foundation for the idea that danger lurks just outside the bungalow.
The next night, after Rikki has already met Nag and Nagaina and almost died from their efforts against him, he finds Chuchundra "creeping round by the wall." Chuchundra's sniveling fear, although comical, creates suspense, as Kipling indicates Rikki can never rest because "Nag is everywhere."
The greatest foreshadowing is when Rikki overhears Nag and Nagaina's plot to kill him. Rikki learns the snakes plan to kill Rikki, Teddy, and Teddy's parents so the mongoose will leave the bungalow and they won't have to fight Rikki. As much as readers care for Rikki and don't want him to die at the mouths of the snakes, they are even more horrified to hear the snakes plan to murder people. This brings the suspense from the foreshadowing to its highest point as readers now know the lives of three humans depend on Rikki's success against the cobras.