Armored Transport

A 2/1 colorless body that does not die when blocked: that is the whole pitch, and it makes the card aggressive by construction. The prevention reads against creatures blocking it, so it is purely a function of attacking. Send it in and a defender faces a sour math problem: a single chump trades nothing, a double-block still kills nothing (all of those blockers' damage is prevented), and the only way to profit on the swing is to find removal, to block with something whose toughness survives the two damage swung back, or simply to take two and move on. The crucial restriction is that the prevention works one direction only. It protects nothing when the construct sits back on defense, and it grants no protection against noncombat damage, against being removed outright, or against blockers it cannot kill. That narrow window is what keeps a recurring evader from being a real threat: it is not unblockable, it just cannot be ground down in the red zone, so a controlling opponent always has clean outs (chiefly any wall with three toughness, which eats the attack indefinitely). With no other text, the body is the rest of the story, and a 2/1 frame keeps the floor low. The design tension is that the ability rewards a single play pattern (a lone, repeated attack) while doing nothing to address the fragility that matters everywhere else: durable in combat, irrelevant the moment combat ends.