1st edition base set booster box for sale Pokemon 1 Shadowless Limited Printing Cut in Shrink released in 1999 Pokémon Booster Box Sold $408,000

They are special cards that show the Pokmon's artwork across the entire card instead of restricting it to the art box

costco.com/pokemon-151-bl

As you can tell from the Twitter post (assuming that you can read Japanese), this is meant as an incentive for Japanese audiences, so no point chasing after these in your English Collector Booster boxes

You can then recast it again and again, gaining more and more life with Aetherflux Reservoir each time until you're ready to blast everyone

When everything came together I was able to just crush everyone, but that wasnt happening nearly enough for me to be comfortable taking the deck to a large event