(Choose any number of permanents and/or players, then give each another counter of each kind already there.) To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents
The proof will be in how many players Pokmon TCG Pocket potentially ends up banning for this sort of thing, and if it publicizes those numbers as has become common across lots of other online games
Kitt Kanto, in all actuality, is a great hatebear style Commander, and should see more play than shes currently seeing
So, you really can't go wrong throwing Nature's Rhythm into basically any green deck with a bunch of creatures
Flavor-wise, picture everyone freaking out and running away from a particular creature before just going back to normal