Muscle Burst

A pump spell that scales off its own corpse. With no copies in any graveyard the math comes out to +3/+3, the exact swing of Giant Growth for one extra mana, which is no bargain on its own. The hook is that X counts every card named Muscle Burst sitting in any graveyard, so a deck running the full set turns each successive cast into a steadily larger boost as spent copies pile up. The reward structure is a deckbuilding constraint in disguise: the spells you have already burned feed the ones still in hand, which means it pays players who commit four slots and punishes the splash. There is a wrinkle in the wording: "all graveyards" includes your opponents', a clause that almost never matters but is a real lever in the rare mirror. As an exercise in self-referential counting it predates the much larger family of cards that tally identically-named objects, and it does the work at instant speed, so the size of the swing stays hidden until combat math is already locked in: a defender who blocks a 3/3 can find themselves staring at something a good deal larger before damage resolves. This is graveyard-as-resource design that treats the yard as a deliberate engine rather than a dumping ground, with the cost of admission being a single copy that is just an overpriced Giant Growth.