>>44674322Drilbur, Audino, Emolga, Ducklett are exclusive to dust clouds/shaking grass/shadow encounters but they're server-side, in all of Unova there can only be 1
Every now and then when someone finds it they announce it in global chat so people can go there, or you can ask around and hopefully someone spotted it
Also you can get other pokemon/items in there so if you're unlucky you'll have to hunt phenomena multiple times, i think i got to 5 while i was in Unova but never got any exclusive
Once i got to another region i didn't bother anymore since it's a hassle to change regions every time