Voltaic Construct + Xenic Poltergeist + Basalt Monolith

Voltaic Construct

Xenic Poltergeist

Basalt Monolith

How it works

1. Animate Basalt Monolith using Xenic Poltergeist.
2. Activate Basalt Monolith by tapping it, adding CCC.
3. Activate Voltaic Construct by paying 2, untapping Basalt Monolith.
4. Repeat from step 2.

This clever loop turns ordinary rocks into a self-sustaining mana engine by bending the rules of what an artifact can do. First, Xenic Poltergeist steps in to animate Basalt Monolith, transforming the heavyweight mana source into an artifact creature. Once it's alive, you can tap it for three colorless mana, then use two of that mana to activate Voltaic Construct's ability, untapping the freshly animated Basalt Monolith. Because the cost to untap is less than the mana produced, you are left with a net gain of one colorless mana per iteration, yielding an infinite supply.