Automated Assembly Line + Gonti's Aether Heart + Demon of Dark Schemes + Megatog

Automated Assembly Line

Gonti's Aether Heart

Demon of Dark Schemes

Megatog

How it works

1. Activate Automated Assembly Line by paying EEE, creating a 3/3 Robot artifact creature token.
2. When the Robot enters the battlefield, Gonti's Aether Heart triggers, causing you to get EE.
3. Activate Megatog by sacrificing the Robot.
4. When the Robot dies, Demon of Dark Schemes' second ability triggers, causing you to get E.
5. Resolve the Megatog ability, giving it +3/+3 until end of turn.
6. Repeat.

This loop turns an efficient energy engine into a self-sustaining cycle of creation and sacrifice, using Automated Assembly Line to continually spin out 3/3 Robot artifact creature tokens by spending energy. Every time one of those tokens enters the battlefield, Gonti's Aether Heart chips in with a fresh influx of energy counters to help keep the assembly line moving. From there, Megatog steps in as the sacrifice outlet to devour the newly minted Robot, which immediately triggers Demon of Dark Schemes to harvest the dying creature's essence for yet more energy. Because the energy generated across these triggers matches the cost to fund Automated Assembly Line anew, you can feed the machine indefinitely while pumping Megatog to monstrously large proportions.