Optical illusion.

Last month I was in my kitchen and it was half-dark, and one of the peaches that I had on top of my fridge on the metal tray where I keep my fruit until it ripens looked like it had a rather large bump of mold on it, only I knew that that couldn't be what it was, so I thought to myself what it could be, and I finally hit upon the idea that the little sourcing sticker that they put on it had peeled up around the edges, and that that's what I was seeing.

And, I got closer to it, and I was right.