The mystery of the soap

This morning in the shower I used my Lush Karma soap. I only have a little left, about 1.5 x 1.5 inches maybe. I used it and then set it back on the soap holder. At the end of my shower I looked down and it was gone. Now, of course it could have gotten knocked off, but I never noticed it, and I could have set it somewhere weird but I couldn't find it, and maybe the water dissolved it all? Or maybe it's stuck to the back of my arm or something and I just don't know. None of those seem logical at all. My next round of thoughts was that someone was in my apartment and snuck in and stole it when I wasn't paying attention. No, I don't do drugs in the morning if that's what you're wondering. I just seriously have no idea where my soap went. And now I have none left and I want more! If anyone has a more scientific theory I'd love to hear it because this totally baffles me.