Giltgrove Stalker

Evasion priced for the early turns, with a clause that draws its line at exactly the right place. A 2/1 for two mana wants to attack, and the restriction here keeps it doing so against the chaff that usually walls aggressive starts: tokens, mana dorks, the one-drops a defensive deck deploys to brick the ground. Power three or higher can still stop it, which is the honest tradeoff. This is not unblockable; it is unblockable by small things, and most of what gets in the way of a turn-two creature is small. The clever part is that the threshold is fixed rather than scaling with the Stalker's own power, so pumping the body does not widen the evasion: a green deck that grows this thing past the blockers it could already beat in combat gains nothing on that axis, while the same growth makes it harder for the few legal blockers to trade up. A cheap aggressive body paired with a filter that ignores precisely the defensive layer cheap aggressive bodies struggle against: that alignment is the whole reason it reads as more than a curiosity. Green has a long history of trampling over small blockers; this does the same structural job by refusing the block outright rather than spilling damage through it, which matters when the defender's death-trigger or chump value was the whole point of the block.