Proliferate and Prosper

Ok, new keyword that just blew my brain. Proliferate: choose any number of permanents and/or players with counters on them, then give each another counter of a kind already there. Not word for word quote, but there it is. Think about Planeswalkers, Pyromancers Ascension, Infect, and so much more. Half of the walkers can go off the second turn after casting with it, and Pyromancer goes online faster. Slide in a few Training Grounds to make it cost less, and this is going to get crazy fast. I'm seeing it as meta-changing, which it probably won't but it may. Get all cards said while they're still cheap.