That title is a snippet of roadside bathroom graffiti that my hero Stephen King immortalised.
We don’t have a fan-vent in our bathroom. Well, we do, but it is a very current work in progress and it literally doesn’t have a current as of yet. So whenwe bathe, the tiny room gets all steamed up. Since I have plants in there that I don’t want the cats to eat, the only ventilation is to open the small top window.
Himself had a shower on Tuesday morning, and when I got home that evening I immediately saw this on our shower curtain:

That looks like bird-poop to me! All we can figure is that a small bird came in through the open window, perched on the curtain rail long enough to stain the curtain forever, and got back out. Without knocking anything over in a panic, which is pretty impressive!