Sinkhole Surveyor

Attacking is the only way to feed this thing, and that constraint is the whole shape of it. The endure trigger fires on the attack step, not on entry and not off a mana sink, so every point of value is paid for by committing the body to combat and shaving a life off your total as it swings. From there the choice forks: grow into a single evasive flier that outclimbs the board it keeps running into, or peel off a Spirit and leave the 1/3 where it stands, building a wider battlefield that a sacrifice shell can actually use. Those two lines point in opposite directions, and the incremental life loss is what stops the fork from being free: you are financing the engine out of your own totals, so it only pays off when the pressure you generate outruns the attrition. A stalled board turns it inert, which pushes it toward decks that keep swinging rather than durdling behind blockers. As a body it is a compact bit of glue for a black-white counters-and-bodies plan, small enough to trade poorly on its own but happy to convert repeated combat into either a threat or fuel, depending on which half of the shell around it is hungrier.