simpliy the dark spot leading to sootopolis you have to use dive
use dive
in sootopolis city
sootopolis city
sootopolis city
underwater near sootopolis city
Sootopolis city.
Underwater around sootopolis city and mossdeep city
Underwater, in the grass outside Sootopolis City.
sootopolis city
Sootopolis city but you cannot go in.
you dive at route 128 by sootopolis city
In the sootopolis city gym.
It's in the Cave of Origin in Sootopolis city.