Monk of the Open Hand

Prowess asks for a temporary lift: cast a noncreature spell, swing bigger for a turn, then watch the creature snap back to its printed stats. Flurry of Blows changes the arithmetic. The counter is permanent, so every turn you fire off a second spell the body ratchets up one notch and stays there, turning a spells-matter shell into a slow but durable clock. The gating detail is the load-bearing one: the trigger keys on your second spell, not your first, and it fires only once per turn no matter how many more you cast. That single-count ceiling is what keeps a one-mana 1/1 from spiraling arbitrarily fast; it wants a deck that reliably chains two cheap spells a turn, not one that empties its hand in a single storm-style burst. What you get for that discipline is durability a prowess pump can never offer: the growth is locked in, so a sweeper that leaves the creature alive can't strip away the counters it has already earned. The trade is honest, though, and it cuts both ways. Because counters live on the object and not on the card, bounce and blink undo the work: return this to hand and it comes back as a fresh 1/1 with nothing earned, exactly as a reset prowess creature would. It rewards a deck that already wanted to double-spell, and it punishes any interaction that makes the creature change zones.