The Key to the Vault

The reward scales with the hit, and that is the whole engine. Most impulse-draw effects in blue read a fixed number of cards; this one reads as many as the combat damage the equipped creature dealt to the player, and it does not stop at looking: it lets you cast one of them for free. Because it counts damage rather than power, trample bleeding a point past a blocker, a damage doubler, or any pump on the attack all feed the dig directly, while prevention or a fog shuts the whole thing off. The two halves reinforce each other, but they pull deckbuilding in a specific direction: dealing more damage digs deeper, and the deeper you dig the likelier the free cast is something expensive and game-warping, so the incentive is not merely to hit hard but to load the deck with high-cost payoffs worth stealing off the top. It punishes a flat curve and rewards a bimodal one. The blue-locked equip cost keeps it from being welded to any aggressive shell; this wants a controlling deck that can protect one connecting threat rather than a go-wide board. And because the trigger keys on combat damage to a player specifically, it does nothing on defense and nothing into a wall of blockers, so it inherits the oldest problem every equipment value plan has faced since the first sword: getting the carrier through. The free cast collapses the usual gap between finding a bomb and having the mana to deploy it, which is why it reads as more than a straight card-advantage tool.