Brood Birthing

The conditional tripling is where the design lives: a single Eldrazi Spawn already in play turns this from one body into three, which means the spell scales hard off a board you have already committed to building. The asymmetry between the two outcomes is the entire reason it exists. With the condition met, you net three 0/1 chump blockers that each tuck away one colorless mana for later; cracking all three returns three mana against the two you spent, but only by trading away the bodies, so you are choosing between a wall and a ritual rather than getting both. Without the condition, it limps in as a single overpriced token, which is the gating that keeps the upside off the player who cast it cold. That restriction ties the card to a specific build order: you have to be deep into the Spawn engine before it pays. It points at the dual nature of Eldrazi Spawn themselves, which were always part stalling body, part deferred mana, and Brood Birthing is the payoff that converts a row of disposable 0/1s into either a sudden burst of colorless or fresh fodder for a sacrifice outlet. It rewards the player who arrived with an engine and punishes the one who showed up hoping to find one.