Something coming at you at the speed of light is invisible—any little glint warning you of its approach arrives at the same time as the thing itself. There is no possible way to see it coming, or even to know that anything has gone wrong. If it approaches you from below, there will be a couple of nanoseconds during which your feet no longer exist while your brain still thinks it is looking at them. Fortunately, the process is also entirely painless: at no point will your nerve impulses be able to catch up with your disintegration by the bubble. It’s a mercy, really.
