Gather Courage

The pump is generic; the casting cost is the whole story. Convoke turns a board of creatures you already control into the resource that pays for it, which means in a developed token or go-wide position this combat trick frequently costs zero actual mana. That is the design point: a free +2/+2 at instant speed wins combat steps and ambushes attackers without the tempo penalty a real one-mana spell would extract from a swarm deck mid-attack. The catch is structural. Convoke only refunds you when you have untapped creatures to spare, so the decks that want this most (aggressive token shells racing to empty their hand) are exactly the ones most likely to have tapped everyone out attacking. Tapping a creature to cast it also pulls that creature out of the combat math, which can quietly cost more board presence than the +2/+2 returns. It rewards the player who holds back one blocker or develops one extra body specifically as fuel. Within the go-wide green tradition, it stands as an early proof of concept for what convoke could do: let an alternative cost tied to creatures-as-mana run a swarm on a curve that does not actually exist. The rate is unremarkable. The price you can pay for it is what made the mechanic worth printing.