Empyreal Voyager

Most energy producers hand you a fixed allotment: two counters when this enters, one per turn from a tapped artifact, a flat number stapled to an attack trigger. This one scales with the clock instead, paying out energy equal to combat damage dealt to a player, which means the evasion stack is the whole point. Flying and trample together do double duty here: they make the connection reliable, and the harder the connection lands, the deeper the energy reserve fills. Pump it once and you are not just dealing more damage, you are minting more fuel, the kind of compounding return that turns a 2/3 into the centerpiece of an engine rather than a beater. The tension the design has to manage is obvious from the shape of the ability: a card that converts damage into a snowballing resource needs a fragile-enough body that it cannot simply be left unanswered, and a 2/3 sits squarely in removal range. The reward is gated behind a creature that has to survive a turn and then survive the block, so the energy never arrives for free. It is a clean expression of the energy mechanic's most interesting idea, that the resource should be earned through board presence rather than dispensed by a counter, and the better your evasion suite gets, the faster the reservoir grows past anything a fixed-output enabler could match.