Burdened Stoneback

A 4/4 body on a two-mana white frame is a rate the color almost never gets, and the pair of -1/-1 counters is the ledger that pays for it: as printed, this walks in as a 2/2 with a bigger Giant stored inside. The activated ability spends that stored stat line as fuel. Every counter removed grants a creature indestructible until end of turn while adding a point in each direction back to this body, so the card unwinds itself: two protective activations later, the marks are gone and a genuine 4/4 stands where the 2/2 was. Protection here is not a real cost, then; it is a buff you have deferred. What actually constrains the card is timing. The ability is sorcery-speed only, and the indestructible expires at end of turn, so the two clocks bind together: you can only shield on your own turn, and the shield lapses before the opponent acts. That rules out the reactive save against a combat trick or a burn spell on their turn; what it does cover is your own aggression, walling a threat through blockers or holding a key creature alive across your own board wipe. Note the seam indestructible leaves open, too. A creature dropped to zero toughness by another -1/-1 counter effect still dies, which matters against any deck stacking that kind of removal. Spend the counters when your own turn demands it, and the leftover reward is a larger Giant once the shield work is done.