Early editions of the story name him as Sahi. Kipling may have changed the name because he felt that the porcupine needed a more "prickly-sounding" name.
In Pamela Jekel's story "The Porcupine and the Poison People" in her Kipling pastiche The Third Jungle Book, Mowgli and Ikki spend some time playing tricks on each other, until Mowgli falls into a nest of hostile cobrass and Ikki has to bring help.