I came across this stuck to my fence. I looked at it from every angle, but I still can’t figure out what it is. Does anyone know what it is? Check the first comment for the answer

But then, something small caught my eye. At first, I didn’t even pay much attention to it. It was just a spot on the fence. Nothing unusual… or so I thought

From a distance, it looked like a bit of dirt or maybe some residue stuck to the metal. You know the kind of thing you ignore because it’s not worth the effort of figuring out. But for some reason, I decided to take a closer look.