Sorry, but the fog isn't exactly same effect, since its custom made by someone, which i couldn't reach. But you can use other effects use shortcut key ctrl + x
Invisible creatures show up as the blue magic effect, and are still attackable while invisible.
which version should i download then if im playing 7.72?
to be said, its a custom one, i like the addons thingy, and user-own interface so i wanna try it out, reminds me of world of worcroft lol