With more than respectable stats of 6000 power for 5 DON!!, Marco will KO an opposing character with a power equal to or less than 3000
You wont see much traction on TCGPlayer without a full shop on the site, but anyone can list goods on eBay
Its an important distinction to make, because if a mechanic is not inherently broken in all cases (and very few are) then you can make the case for a new set figuring out how to implement them in a way which avoids the pitfalls of previous overpowered designs
Its sorcery speed, so you cant pull a removal on an opponents turn, but when it comes to you, if you have the mana, you can get out of any bind with this card
MTG isnt really built to allow for this physically (the ill-advised experiment with stickers in Unfinity notwithstanding), so this is a virtual change only that needs to be remembered by all players or signaled with a reminder or a written note