The true form of the Lucent Moonfox is ... just an ordinary fox.

Well, not completely ordinary: Streaming down its back are eight distinct "tassels" of fur that help protect it from predators, and the fox can fan them out like peacock feathers, hence presenting some appearance of nine tails. Coupled with the fox's innate ability for illusions, those extra tails can appear very real.

The lower image was inspired by this icon I found while hunting for references.

8x5", inverse colored pencil.