Voltaic Construct + Heronblade Elite + Transmogrifying Licid

Voltaic Construct

Heronblade Elite

Transmogrifying Licid

How it works

1. Activate Heronblade Elite by tapping it, adding at least 3.
2. Activate Voltaic Construct by paying 2, untapping Heronblade Elite.
3. Repeat

This clever loop centers on turning Heronblade Elite into an artifact creature so that Voltaic Construct can repeatedly untap it using the mana it produces. To make this work, Transmogrifying Licid must first use its ability to attach itself to Heronblade Elite, bestowing the crucial artifact type that bridges the gap between the two engines. Once the Elite is an artifact creature, tapping it for a massive pile of mana allows you to feed Voltaic Construct's untap cost with plenty to spare, yielding infinite colored mana and infinite untaps.