Cursed Ronin

A 1/1 for four mana reads like a non-body until you notice it carries its own mana sink. The black activation is the lever: rather than swelling only when it walks into a combat it chose to enter, this one climbs at instant speed for as much black mana as you can spare. Bushido 1 sets a guaranteed floor in any combat it joins, whether it attacks into a blocker or holds the line on defense, so even with no mana open it trades up to a 2/2 the moment it blocks. The firebreathing-style activation lets it push past whatever that combat math suggested, turning the smallest of bodies into a removal-baiting attacker or a surprisingly stubborn wall. The tax is that every point of size beyond the bushido bump costs a black source, so the card is only as large as your untapped mana, which places it in the lineage of repeatable pump creatures that ask you to leave land back rather than burn a one-shot trick. The order of operations is the wrinkle worth holding onto: the bushido trigger fires during the declare blockers step, once the creature blocks or becomes blocked, and the activated ability stacks on top for as long as you keep paying. A defender sizing up the attack has to account for both an automatic +1/+1 and an open-ended one, which makes the math a guess rather than a calculation.