Ambitious Augmenter

Increment inverts the usual growth trigger: instead of rewarding cheap, high-volume casting, it rewards spending big. A one-drop that starts as a 1/1 grows only when a spell you cast costs more mana than its current power or toughness, so each counter it gains raises its own threshold. The early counters come easily; later ones demand genuinely expensive spells, which turns the card into a running ledger of how much bigger your plays have gotten. That escalating bar is the balancing wrinkle: it will not snowball off a hand of cantrips, and it caps itself against a low-curve deck. The death clause is where the design earns its second look. Rather than losing the accumulated counters when it dies, it hands them off to a fresh 0/0 Fractal, a body that would evaporate without exactly those counters to hold it up. The counters are never wasted; they migrate. That gives the creature a strange durability against removal, since killing it converts a growing Wizard into a token carrying its counters, and the Fractal's blue-green identity nods at the shard-of-a-mind flavor that so often accompanies +1/+1-counter matters. The result is a green one-drop whose value is measured not by its stat line but by the size of the spells you cast around it, and whose payoff is a promise that its counters outlive it.