Satya, Aetherflux Genius

The token clause is the whole engine, and it runs on a deliberate shortfall. Copying one of your own creatures on attack is old territory, but this design hands the copy back at end of turn unless energy pays its way, and the attack itself only produces two energy per swing. That gap is the tension: keeping a token past this turn costs energy matching its mana value, so the deck has to source energy elsewhere or accept that most copies are single-swing attackers. The result is a recurring decision about which creature is worth copying tapped and attacking right now versus which one you can actually afford to retain. A cheap value creature is nearly free to keep; a fat finisher demands a real energy stockpile, which pulls the build toward an energy economy instead of a heap of expensive bombs. The body is built to keep the attacks coming: haste turns it on the moment it resolves, menace pressures blockers so the swings keep landing damage rather than getting eaten, and the 3/5 frame survives combat well enough to trigger again next turn. Notice the trigger fires on declaration, not on connection: even a fully blocked attack still spawns the tapped copy and banks the two energy, so the engine never stalls out on a good block. This belongs among attack-triggered token generators, but the energy tax reframes the classic "copy your best creature" line as a resource question rather than an automatic blowout. What you build around it is not a stack of copy targets; it is a machine for financing the copies you want to keep.