This .2da override will make all creatures that have been scaled 80% or lower non-targetable.
That means that it will remove the large highlight glow around any small creatures.
All you need to do is put this appearance.2da file in your overrides folder. It then overrides the origional appearance.2da. Of course, this won't work if you already have an appearance.2da override!
It looks like you need to right click and Save As to download the file. Remember, don't change the name or it won't work.