You decide that going far into this cave may lead you to getting lost, or worse, so you decide to go back and maybe explore the cave another time.
As you make it back, you're careful to not step in anymore bat guano, but when you return, you find that the puddle of bat guano had vanished.
"Weird..." you say, but dismiss it as one of those weird but don't care about mysteries.
You make it to the cave entrance, but stop. Why?