Quandrix Command + Crystalline Crawler + Dualcaster Mage + Loading Zone

Quandrix Command

Crystalline Crawler

Dualcaster Mage

Loading Zone

How it works

1. Cast Quandrix Command by paying its mana cost, choosing its first and third modes.
2. Holding priority, cast Dualcaster Mage by paying its mana cost.
3. When Dualcaster Mage enters, it triggers, copying Quandrix Command, with the copy's first mode targeting Dualcaster Mage and the copy's third mode targeting Crystalline Crawler.
4. Resolve the copy of Quandrix Command, returning Dualcaster Mage from the battlefield to your hand and putting four +1/+1 counters on Crystalline Crawler due to Loading Zone.
5. Holding priority, activate Crystalline Crawler three times by removing three +1/+1 counters from it, adding 1.
6. Repeat from step 2.

This clever loop uses Loading Zone to supercharge Crystalline Crawler, turning its native ability to convert +1/+1 counters into mana into a profitable engine. When you cast Quandrix Command and duplicate it with Dualcaster Mage, the copy bounces Dualcaster Mage back to your hand while loading up Crystalline Crawler with double the counters. You can then use Crystalline Crawler to peel off those extra counters for mana, generating a surplus that easily recasts both Quandrix Command and Dualcaster Mage to do it all over again.