To say something is its own animal (or beast) [or that it is a beast/animal of its own] is to say that it is unique, sui generis, that it follows its own laws and will, that to understand it it needs to be taken on its own terms, it has no precedent. It's not so uncommon, from "The Republican primary is its own beast—a once-in-a-generation unsolved mystery that cannot be compared to 2004, 2008, or 2012. With Ted ..." and "Los Angeles is unlike any place I have ever lived in. I've spent a lot of time on both coasts, but I can safely say that LA is its own animal" to "Remember, your metabolism is a beast of its own, so feeding it in portioned out, frequent meals can often be your best bet at maintaining"; or "Bristol is an animal of its own. It's a very unique racetrack. When we race there, the speeds are lower, and the baking holds the car to make the ..." How to get that over compactly into G.?