Might of Old Krosa

The split rate is the whole design: cast this before combat on a turn you control and a single green pip buys +4/+4, but use it as a combat trick on either player's turn and you collapse back to a respectable +2/+2. That conditional inverts the usual logic of a pump spell. Most cheap green tricks pay for their efficiency by demanding instant-speed timing, where the surprise is the point; this one hands you its biggest number precisely when you cast it with the least surprise, before combat, with the bonus already on the board for the opponent to see and block around. The trade is information for power. Pump at sorcery speed and you commit to a fixed, telegraphed threat, asking the opponent to find an answer to an attacker four points larger than the body they were planning for. Hold it for combat (to ambush a blocker, or to rescue a creature from removal at instant speed) and you keep the surprise but surrender half the bonus. That tension is the engine: the card rewards the proactive beatdown plan that wants raw size pushed onto the table as early as possible, and it quietly taxes the reactive lines that want to wait. For a deck whose whole proposition is racing the opponent into the ground, the main-phase number is the only one that matters; the combat-trick mode is the safety valve that keeps this from being a strictly better one-mana pump spell.