Isn't it amazing how quickly the human legs can move somebody? It's not something people often think about... but now you are. But now I'd like you to imagine how quickly something not quite human can move.
You don't know. You can't know. You have no idea what I'm referring to. But that's just it. You'd have to know in order to know. Confused? Good. Distracted? Better. There. Did you see it? Of course not. It didn't matter that it can't move so quickly, and you read this slower than it can move.
You didn't notice, did you? You didn't notice it creep through your door and into your closet. Don't bother checking. It will be under your bed by then. Or maybe it's already there. Be quicker next time. If there is one.