Hagi Mob

Boast exists to give a body a reason to keep swinging into unfavorable blocks, and this 5/4 Troll Berserker is the clearest common-level demonstration of what the keyword is trying to reward. It is already a beater that trades up on offense, but the boast turns each attack step into a repeatable pinger: attack first, then spend to throw a point of damage wherever it helps, once per turn. The sequencing restriction does all the balancing work. You cannot hold the mana up defensively and fire it off on the opponent's turn; you have to commit to the attack, expose the creature, and only then unlock the ability. It converts a vanilla-ish beatstick into a slow-burn engine that grinds toothy one-toughness creatures off the board or chips in that last point of reach, but only if you are the one dictating combat. The design lesson is in how boast couples cost to aggression: the ability is cheap because the prerequisite is a tax paid in tempo and vulnerability, not mana. As a Troll Berserker doing exactly what a Troll Berserker should, it illustrates cleanly a keyword built to punish passivity.