Voltaic Construct + Karametra's Acolyte + Transmogrifying Licid

Voltaic Construct

Karametra's Acolyte

Transmogrifying Licid

How it works

1. Activate Karametra's Acolyte by tapping it, adding at least .
2. Activate Voltaic Construct by paying 2, untapping Karametra's Acolyte.
3. Repeat

This clever loop turns Karametra's Acolyte into an unstoppable mana engine, provided your devotion to green is at least three to ensure a net positive return on every cycle. Because Karametra's Acolyte is naturally a creature rather than an artifact, Transmogrifying Licid steps in as the crucial bridge, transforming it into an artifact in addition to its other types so it can be legally targeted. Once properly classified as an artifact creature, Voltaic Construct can repeatedly untap it using a portion of the generated green mana, leaving you with infinite green mana and infinite untaps.