For example, a creature that enters the battlefield with one +1/+1 counter on it won't receive an additional +1/+1 counter
This is an excellent card to have in play just in case you've got three mana available at the end of your last opponent's turn so that you can bank it as energy before you untap
Notice how the black of the mana symbol and surrounding text are made of rosettes, and not black throughout
Songs and actions like A Whole New World refill your hand and set up combos, while disruption cards make sure your rival never feels safe
Your opponents wont be attacking or removing it from play in fear of what can come after, be it Omniscience, Cacophony Unleashed, Battle at the Helvault, or what have you
Remember, class enchantments stack, so you can play multiple copies and trigger their abilities simultaneously, but each card needs to be leveled up separately