Moonfin

Moonfin is a fictional creature that appears in the "Starfall" universe, a science fiction role-playing game and novel series. It is depicted as a bioluminescent, aquatic organism native to the ocean moons of various planets. The creature is characterized by its large, moon-shaped fins that emit a soft, pulsating light, which is believed to be used for communication and navigation in the deep, dark waters it inhabits.

Physically, Moonfins are described as having sleek, streamlined bodies, often with a translucent quality to their skin. Their diet consists primarily of plankton and smaller aquatic life forms. While generally peaceful, they are known to exhibit defensive behaviors when threatened, primarily through rapid bursts of light to disorient predators or by employing surprisingly strong tail propulsion to escape. Encounters with Moonfins are often considered a rare and beautiful sight by explorers and inhabitants of these alien worlds. Their biology and ecological role are subjects of ongoing study within the Starfall lore.