Gitaxian Raptor

A 1/4 flier with a self-destruct budget stapled to it, except the budget only bends the body temporarily, which is the whole trick. The three counters are set at entry and never replenished, and each one buys a +1/-1 that lasts only until end of turn: spend one and it swings as a 2/3, spend all three and it comes crashing in as a 4/1 in the air. Then the turn ends and it snaps back to 1/4, none the worse. That resilience is what makes the counters worth hoarding rather than spending. Flying does more work here than the stat line suggests, because it lets the creature pick its combats: it sits behind as a hard-to-kill wall on the turns it wants to block, then converts stored toughness into evasive damage on the turn it wants to attack, and reverts to a defender once the turn ends. The one-way ratchet is the real constraint. The counters are a spend-once pool, so the tension is not durability-now versus damage-later (it keeps its durability from turn to turn) but how many of a finite three attacks you cash out this turn. Burn all three and it hits for four exactly once; ration them and it threatens meaningful damage across several turns while retaining most of the toughness that keeps it alive.