I got a trubbish today and I noticed that it states in its pokedex entry that it was made by pollution
Now i know this sounds far fetched but listen...
Grimer was also made by polloution but it's just slime where as trubbish is a solid from.
I believe that trubbish would use gunk shot on the water in unova.
It would get swooped by a current and brought to the sea's of kanto.
It then used the polltion in kanto to create it self.
Basically what i'm saying is grimer is a sub-offspring of trubbish.
And since garborder is a bigger trubbish muk is a bigger grimer post your thoughts below