Acridian

Four toughness on a green two-drop is a real number: it walks under most early burn and absorbs the small attackers that define the first turns of a game. The problem is the keyword bolted onto it. Echo's bargain is to front-load a body above its mana value, then dare you to keep it: pay again next upkeep or sacrifice it. That gamble is only worth taking when the discounted turn buys something you couldn't get at fair rates. A 2/4 ground wall isn't that. The first cost gets you an unremarkable blocker; the echo payment buys you the same blocker a turn later, no upgrade, no payoff, just rent on a creature whose entire function is to stand still and stop one attacker at a time. That's where echo curdles from discount into tax. A defensive body has no above-rate ceiling to discount in the first place, so the mechanic's tension never engages; you pay twice for an effect that was never exciting once. As a common, this filled out a creature curve and asked nothing of the builder beyond the green to cast it. What it does illustrate, cleanly, is the edge of echo's design space: stick the keyword on something with no upside to front-load and you get a creature that punishes you for keeping a wall, which is the opposite of what a wall is supposed to do.