Well, obviously not a real moon. But her marking sure looks like it! You know, a crescent moon, only it's kind of on the side on Luna.

[Even here, in some strange new place, she isn't quite the most forthcoming on the details. On how and why. How Luna is actually pretty special for a cat. Still, she gives Hikari that much, as they try to progress and follow. See if this direction might yield any results in getting out.]