s9a pokemon card list Battle Legion Booster Box TCGplayer - Pokemon Japan S9a:

While Im unclear on the lore significance, The Flesh Is Weak is a very unique card design that puts +1/+1 counters on your team and turns them into artifact creatures

It's most often played in decks that can ramp into it quickly, most notably Eldrazi Breach decks in Modern, and pops up in niche Sneak and Show builds in Legacy

However, given that it's so high up on Mark Rosewater's "Storm Scale" meaning the mechanic is unlikely to return it would likely be a similar mechanic with a twist

This isn't one for collectors or hardcore players, but for casual and new players who just want to grab a could of booster packs and play