When The Ghost Hits The Fan

If you run a common desk fan long enough, grimy gunk will accumulate on the blades.
Sure, a lot of it is dust, but the rest of it turns out to be chopped bits of ghost.
What? You thought that ghosts were person-shaped specters or flapping empty-eyed sheets floating in the air?
Well, I’m not sure about that. These bits and fragments are rather small, but I’ve collected up enough to take a guess.
What is it a ghost of? A person?
Actually, based on what I’ve got so far, I’d say it was a ghost of a dust bunny.