I think I’ve figured it out, actually. There is nothing on the bathroom floor that wasn’t always there, namely, the scales. The sound I heard was definitely not Kenny (the cat) jumping down from somewhere. Kenny is either prone to chasing and jumping at tiny bugs that I can’t see, or he just likes to dart off in any random direction from a sitting position, just because he’s young and frisky. He must have been sitting on or near the scales, took off suddenly, and jostled them, thus creating the mysterious sound. This theory is further bolstered by Count Blucher’s idea. Kenny does indeed have body image issues. Just the other day he was going on and on about how he needs to lose and ounce or two. I’ve removed the scales. He was getting obsessed about it…