Aetherwind Basker

A green energy payoff built to convert a wide board into an arbitrarily large threat, and the rare card that makes energy a closed loop rather than a slow drip. Most energy designs of its era spent counters as a side benefit; this one both generates and spends them on the same axis. Each entry or attack pays out one counter per creature you control (it counts itself, so even into an empty board it banks at least one), and the pump sink turns those counters straight back into power, so a developed board lets it grow far past its printed 7/7 in a single attack step. The trample is what stops overflow from being chumped away: every point of pump you buy is a point that has to be answered, not absorbed. The timing is what makes it sing. The attack trigger resolves during the declare-attackers step, before blockers come down, which means you can bank a board's worth of energy and dump it into power while the opponent is still deciding how to block, sizing your trampler against their declarations. That makes it a finisher for a go-wide green shell rather than a standalone bomb: drop it onto an empty board and it is just a 7/7 trampler that grows by one. The reward scales with how much you have already built, which is the honest price of an effect that, fed properly, ends the game in one swing.