The Thirteenth Doctor + Squee, the Immortal + Crystalline Crawler + Ashnod's Altar + Primal Vigor

The Thirteenth Doctor

Squee, the Immortal

Crystalline Crawler

Ashnod's Altar

Primal Vigor

How it works

1. Activate Ashnod's Altar by sacrificing Squee, adding CC.
2. Cast Squee from your graveyard by paying 1.
3. The Thirteenth Doctor's first ability triggers, putting two +1/+1 counters on Crystalline Crawler.
4. Activate Crystalline Crawler's first ability twice by removing two +1/+1 counters from it, adding .
5. Repeat.

This clever loop turns Squee, the Immortal into an endlessly recurring engine, utilizing its ability to be cast directly from the graveyard for {1}{R}{R}. Every time you sacrifice Squee to Ashnod's Altar for two colorless mana, you fuel that casting cost while generating endless death, ETB, and sacrifice triggers. Because Squee is entering from the graveyard—anywhere other than your hand—The Thirteenth Doctor triggers upon casting, targeting Crystalline Crawler to receive +1/+1 counters. Primal Vigor doubles those counters as they are placed, allowing Crystalline Crawler to accumulate an excess of counters that you can immediately cash in for colored mana by removing them. While Team TARDIS and the Crawler's tap ability aren't strictly required for the infinite mana loop, the entire setup yields infinite colorless mana and an infinite storm count to close out the game.