Kalamax, the Stormsire

The word "tapped" in the trigger is the entire strategic pivot. Most cast-triggered payoffs want to be untapped and safe, hiding behind their board; this one demands the opposite, asking you to send a 4/4 into combat or crew a Vehicle so the body is already tapped when your instant goes on the stack. That condition rewires how a whole deck sequences a turn: attack first as a matter of course, then cast into the open window, and the copy comes free. The second ability folds the payoff back into the body, so every copied instant is also a growth trigger, which means the deck's clock and its spellslinger engine ride the same axis rather than competing for a game plan. The copy applies to anything: targeted removal hits twice, card draw doubles into a genuine engine, and each copy plants a fresh +1/+1 counter. The "first instant spell each turn" clamp is what limits the free doubling to one spell per turn, but it is not a hard ceiling on the second ability. Cast a copy-a-spell effect as your first instant with Kalamax tapped, and the Kalamax copy can target the original copy spell, which copies itself, and so on: an unbounded loop of copies that piles unlimited +1/+1 counters onto the body. The commander's most famous line is precisely the one the clamp appears to forbid, which is what gives building around it its edge.