Codie, Vociferous Codex + Galvanic Alchemist + Zirda, the Dawnwaker

Codie, Vociferous Codex

Galvanic Alchemist

Zirda, the Dawnwaker

How it works

1. Activate Codie by paying 4 and tapping it, adding .
2. Activate Codie by paying , untapping it.
3. Repeat as desired, skipping step 2 on the final iteration.
4. Once you have an arbitrarily large number of Codie triggers, cast any spell by paying its mana cost, reduced by the added in step 1.
5. Codie triggers for each time you activated its ability.
6. Resolve the first trigger, causing you to exile cards from the top of your library until you exile an instant or sorcery spell with lesser mana value, and allowing you to cast that spell without paying its mana cost.
7. Repeat step 6 for each remaining trigger.
8. You may also repeat this combo for each instant and/or sorcery card in your hand as mana permits, and on subsequent turns.

This mesmerizing transmutation turns Codie, Vociferous Codex into an infinite mana engine by pairing it with Galvanic Alchemist via soulbond, granting Codie the Alchemist's paired untap ability. Zirda, the Dawnwaker is the true catalyst of the laboratory, reducing the cost of that activated untap ability so efficiently that Codie's ability generates a net profit of colored mana with every single loop. Once you have accumulated an arbitrarily large pool of white, blue, black, red, and green mana, Codie's cascaded ability triggers can be leveraged to cast a subset of spells directly from your library for free.