There are tons and tons of really cool changes animals go through. When you think about it, even the completely normal process of growing up is pretty incredible. A little thing sucks up molecules from its environment and transforms them into the pieces of a changing, growing body.

But the first thing that came to mind when you said "interesting" and "metamorphosis" was the flounder. There are a few types of flounder. It's a fish that's born like any other fish, but when it reaches a certain stage in its life one of its eyeballs literally migrates through its own head and emerges on the other side, so that it has two eyes on one side of its face. The fish then starts lying flat on its side on the bottom of the water, blending in with rocks and such, and swims around completely sideways, both of its eyes pointing up toward the surface off the same side of its head. I think that's fantastic.



The change from summer to winter in northern and southern latitudes has always fascinated me. How everything adjusts or moves in response. Plants, animals, everything.



I find societies that allow a reversion to tyranny, whether quickly or slowly, to be fascinating and horrifying to read about. It's one of the biggest reasons why World War II interests me so much.



Hmm. The life cycle of a star is pretty amazing. I also find the slow transformation of the planet to be incredibly interesting. The shifting of continental and oceanic plates, the erosion and buildup of land features, the rise and fall of mountains, glacial sculpting, the inexorable carving action of moving water, the formation of new rocks far beneath the surface, the creation of minerals, such as the compression of carbon creating diamond.



For this I only have my own experience to draw from, but I enjoy the evolution of a story idea. The book I'm writing at the moment is a conglomoration of several ideas I've been having off and on for the last seven or eight years. I had notions for a number of unconnected books with unconnected characters taking place in the same world, and then it transformed into the notion that what if all of the books had the same character? I had a mechanism in place in one of the books to rationalize that, so I shuffled their order around in my head, added new plot ideas, brought in some ideas from an entirely different story in a different world, and at the end of the process my various ideas had fused into something new and exciting.



The most interesting change in an action? I'm not sure I know what you mean. But trying to smack a flying insect and accidentally knocking yourself in the side of the head because you're so flustered that you've completely lost track of your sense of proprioception is pretty neat.