While the standard Celebi ex is already rare enough on its own, the card also has a full art and an immersive art version
Later supports turned them into a beatstick deck
I know, the FFVII Summon: Knights of Round gives 12, so thats what you get, on top of an indestructible 3/3 creature
Mutating it really isnt too difficult in EDH, and if you start playing around with cards that can have negative power in the graveyard (like Deaths Shadow and Scourge of the Skyclaves), then you can really start doing silly things with it
However, it is awful to come up against, particularly if you have some good traps all ready to go and have to see your perfect plan go to waste
Commander Game Changers The Game Changers for Commander are a Wizards-defined list of cards that are on-watch for their power level, and tied to the deck rating brackets to help players sit down at tables of similar-strength decks