I can't remember the title or author of a fantasy story I read in my elementary school. Specifically, I read this in 3rd or 4th grade. It was a short story, not very many pages. In fact, we had to tear it along perforations out of a booklet, assemble it in order, and staple it together from pages, like a "weekly reader" or something. (Each page was half of an 8.1/2 by 11 sheet.) The story revolved around this young girl who somehow discovers a whole hidden world within our world. She somehow shrinks down to a tiny size - the size of a tiny insect, I believe. Things look very different at that size, obviously. But there she meets a whole society of furry people. The story was well illustrated and they looked like Sasquatches or tall Ewoks. But they had different colored fur (red, green, blue, yellow, brown, etc). These people were friendly to her. But then there were these "giant" humanoid mechanical monsters who occasionally terrorized the furry people. (In actuality, the robots were very small by human standards, but they were much larger than the furries.) Apparently, these clockwork invaders are occasionally sent by some madman or meanie or something. The furries react by running around, until the clockwork monsters that chase them wear out and run down. When a monster gets close, the furry finds something their color for camouflage and hide. The green ones find grass, the brown find a tree trunk, the blue find water, etc. The girl and a furry friend was chased, too. Her friend comments on her color and takes her to a cliff face that was honey-colored to hide. (She had a honey-colored sweater and honey-blonde hair.) After the clockwork monsters run down, the furries go around disassembling them and burying the parts. I believe there was some ecology or Earth-friendly message, too. Anyway, the story ends with the furries telling her how to get home. It turns out that she was on a small "island" and she had to walk underwater to reach her world. They escorted her part way and, yes, they somehow breathed underwater as if it were air. By the time she reached shore she was full-sized again. It was so long ago when I read that. But it seems I still remember quite a bit of detail. It must have had an impact on me. I have to respect the author's wild imagination and creativity.