Mysterious White Fluff (or something like it)

I have no idea what it was, and I can't find it... I was arranging supplies on shelves at work when a white, fluff-like clump passed by my feet. It looked like a dandelion seed, about the size of a baseball. It was too big to be just fluff, and too white to be dust. It went under a shelf, but when I looked, there was nothing there... Even though it went under the shelf, there's about 50cm of space under all the shelves, and I don't keep anything on the floor. It should have been visible, but I couldn't find it anywhere around. It was recently renovated and is very clean, I mop every day, and there are no animals in the workplace. This workplace has no windows, only one door far away, and since it was winter, the air conditioning wasn't on. Coincidentally, there was no one around me; I was alone. Its movement wasn't rolling, but more like it was smoothly gliding... Several years have passed since then, but I still don't know what it was.