Hakbal of the Surging Soul + Agatha's Soul Cauldron + Crystalline Crawler + Hellkite Charger

Hakbal of the Surging Soul

Agatha's Soul Cauldron

Crystalline Crawler

Hellkite Charger

How it works

1. At the beginning of your combat phase, Hakbal of the Surging Soul's first ability triggers, causing you to reveal the top card of your library, put a +1/+1 counter on each Merfolk you control and putting the card back on top of your library.
2. Declare Hellkite Charger as an attacker, triggering its ability.
3. Activate seven Merfolk you control using Crystalline Crawler's first ability by removing a +1/+1 counter from each of them, adding 5.
4. Resolve the Hellkite Charger trigger, causing you to pay 5 to untap all attacking creatures you control and to get an additional combat phase after this one.
5. Repeat each combat phase.
6. If you control eight or more Merfolk, this combo nets infinite colored mana and +1/+1 counters on Merfolk you control.

This loop centers on granting explosive activated abilities across your board using Agatha's Soul Cauldron to feed an engine of perpetual combat and mana production. By exiling Hellkite Charger, its extra-combat ability becomes accessible to any creature holding a +1/+1 counter—a requirement effortlessly met by Crystalline Crawler, which can convert those counters into the exact mana needed to pay for Hellkite Charger's trigger. Meanwhile, Hakbal of the Surging Soul keeps the whole army well-fed with counters via its exploration trigger at the start of combat, allowing Crystalline Crawler to repeatedly generate resources, untap alongside your attackers, and sustain infinite combat phases.