Ngastund, also called ngyzit in the Amur dialect, is the East-Sakhalin Nivkh name for the sung epic tale tradition in which performers tell stories in an improvised, melodic style, to musical accompaniment. The instrumentation includes tambourines, ritual rattles, mouth harps, whistles, a one-stringed bowed instrument called a tyngryn, and tyatya chxach, the drum log.

Storytellers narrate heroic deeds in a vivid, highly emotional performance, with vocalizations ranging across chanting, singing, and howling. In these epic tales, it is common for the hero to act alone, turning for help not to his community but to the spirits of the taiga, mountains, and sea, and to representatives of the animal world like fish, foxes, owls, and espeically bears.