Engaging with a superficially simple folktale from the Kuni of Papua New Guinea, I identify a number of far-flung and quasi-universal themes as well as some widely distributed Melanesian ones. I suggest the main function of the etiological folktale is to obviate aspects of everyday existence, then to restore and reaffirm them. I attribute the grip of etiological tales, more generally, to a human drive for explanation. An added attraction for the Kuni is the sense of solidarity gained in public semi-ritualised retellings. Finally, I analyse some of the 'inside' meanings contained in this tale of Kolukolu and the Moon.