The Fly
The Fly - Biologically, it is understood why the fly is associated with death. Flies, maggots and other insects are attracted to decomposing carcasses. Odors released in the decaying process attract flies to lay eggs. What might be subtle, unnoticeable at first, becomes glaring with the potent presence of the fly.
Regardless, in a shack or luxurious architecture, you know when a fly is present. We can still marvel at the beauty around us, but we will notice. something. is. not. quite. right. This will not deter us from our purpose, but the minute detail will not be missed.
The same as Pluto: teeny-tiny, far far away, so quiet, yet present, noticeable and unforgettable.
Coming across the symbol of the fly acknowledges that regardless of your circumstance, something is not quite right. While this may not keep you from achieving your goal, it is distracting. The fly is subtly influencing the circumstance by calling attention to the transformation occurring.