The nano-stars were clearly artificial in origin, although their microcircuitry was water-sealed and its purpose a mystery. Each star was flat and pentagonal in shape, half a meter in diameter. From each of the star's five corners five small metallic tentacles appeared, although they were not used for movement; nano-stars propelled themselves through water with a number of flexible screws.
Nano-stars did not appear to eat. They protected themselves by zapping an electric current through water if they felt threatened. Nano-stars were assumed to be able to construct new nano-stars, although this process was never witnessed. However, several million nano-stars were believed to exist in the seas of Mon Calamari.
The first appearance of a nano-star took place on the seas near Foamwander City, soon after a colossal metallic sphere descended from the sky, dropped something in the ocean and then vanished again. Fish-catchers netted the first nano-star soon after this had taken place. The origin of the UFO was not explained and experts were confused.