It doesnt shut down static or activated abilities, but most creatures will become useless once this is on it
Truth be told, I live for Magic cards like this, that come down and have some huge splashly effect with a little RNG thrown in
We're excluding multicolor cards as well as cards with other colored mana symbols in their text box like Chatterfang, Squirrel General, so any Commander deck with green can use any of these cards
Whenever possible, we're going to use Legendary and Spider Creatures so we can double those counters too, but we're going to focus on getting counters on pretty much everything and, when we do, having it be a serious problem for the rest of the table
Retrieving your good enters creature and ramping is a nice little interaction