It could have just been a lazy cash-in on the One Piece name, but the One Piece Card Game which is a trading card game, rather than a traditional, fully complete boxed card game as the name may suggest has some really interesting, somewhat innovative mechanics that make it worth playing, even for non-fans
The card otherwise sees some cEDH play, but is rather rare there
I've written at great lengths about cards that make for fun commander games - They are cards that stimulate action in some way
Spark Doubles additional counter opens the door to various synergies with proliferate and other counter shenanigans
It takes its share secretly, one coin purse at a time
In this case, the bonus sheet will contain powerful Legendary creatures