Earthbrawn

The Reinforce keyword exists to solve the dead-card problem that haunts every combat trick: a pump spell held in hand is worthless if the right swing never comes, and this is that keyword in its plainest form. Cast normally, it hands a creature +3/+3 to win a fight or push lethal for two mana. But when the temporary boost has no good target this turn, you can discard the card to put a permanent +1/+1 counter on a creature instead, trading the spell from hand for a smaller, sticky upgrade. Note that Reinforce still needs a creature to receive the counter; it is not a way to do something with an empty board, but a way to bank lasting value when a transient buff would be wasted. The split is deliberately lopsided in size, a large temporary swing against a modest lasting one, so the choice is never automatic: you are weighing whether this turn's combat is worth more than next turn's permanent body. Both modes operate at instant speed, which keeps the counter mode from being a sorcery-speed durdle: you can fire it in response to removal to size a creature out of a burn spell's range, or hold it until combat and decide which version the board actually wants. That timing flexibility is the real payoff of folding two cards' worth of decisions into one.