Delif's Cube

A storage artifact that charges itself by taxing your own offense, which is one of the stranger value loops the early design teams tried. The first ability is the cost: you commit a creature to an unblocked attack, then cancel its damage to bank a cube counter. The second ability is the payoff: spend counters to regenerate. So the card converts a turn of forgone combat damage into stockpiled regeneration shields, asking you to trade tempo now for resilience later. The friction is everywhere. Both abilities cost two generic mana on top of the bank-or-spend transaction, and the charging mode only fires on creatures that connect unblocked, so an opponent can starve the engine by simply throwing a chump in front. The regeneration end of the loop works as advertised (it is a replacement effect that shrugs off the next destruction outright), but getting there is the problem: you have already spent mana, an attack step, and an artifact slot to bank each shield, and a defending opponent controls whether you bank any at all. The result is a converter running at a punishing exchange rate, turning your own combat phase into a regeneration battery that the other player gets a vote on. It belongs to the school of Fallen Empires artifacts built around counter economies and conditional triggers, designs that read as engines but resolve as taxes. The idea (storing a defensive resource by spending an offensive one) is genuinely novel; the rate makes it a curiosity rather than an engine.