The Flesh Is Weak

The design does two contradictory things at once, and the flavor lives in the contradiction: it hands a +1/+1 counter to every creature you already control, then declares that any nonartifact creature shrinks. The counter is not just a stat bump; it is a passport. Get one onto a creature you control and it reads as an artifact in addition to whatever it already was, which pulls it into the orbit of every artifacts-matter payoff, every metalcraft threshold, every "artifacts you control" anthem, and it does so as a static condition that never expires. Meanwhile the -1/-1 clause is a soft sweep pointed at anyone who missed the initial pulse: opposing tokens, mana dorks, anything that isn't an artifact. That asymmetry is the balancing act. The enters trigger only counts creatures already deployed, so the enchantment rewards being ahead and punishes flooding in afterward; a creature you play the turn after this resolves lands at -1/-1 unless you can staple a counter to it first, which for most small bodies means it never survives to matter. The artifact-typing is the sleeper line. It quietly converts a wide counters-matter board into fuel for effects that were never built to see white, blue, or black creatures, without adding a single artifact to your deck. It is a counters engine wearing an artifact-synergy engine's coat, and the friction between "everything I control is now metal" and "every nonartifact is dying" is where the deckbuilding lives.