Mutational Advantage
Green-blue counters strategies live and die on a fragile board state: proliferate is slow, and a deck that spends turns growing +1/+1 counters or ticking up a planeswalker hands the opponent an obvious window to blow everything up in response. This answers that structural weakness directly. Fired at instant speed, it hangs hexproof and indestructible on every counter-bearing permanent you control, blankets them against damage, and then adds to the pile with proliferate, so the same spell that protects the engine also advances it. The scope is the clever part: the buff keys off "permanents with counters," which sweeps in far more than creatures. Planeswalkers, Sagas, artifacts with charge counters, even lands carrying counters all fall under the same umbrella. That makes it a combat trick, a board-wipe insurance policy, and a counters-matters payoff folded into one card, and the proliferate rider means it never sits fully dead: worst case, you flash it in to grow your counters at the end of an opponent's turn. The design logic is that a proliferate deck already wants a permanent to protect and a reason to keep casting spells; this satisfies both obligations at once without asking you to hold up a dedicated counterspell that does nothing when the board is quiet.
