Cauldron of Souls + Zealous Conscripts + Verdurous Gearhulk + Phyrexian Altar

Cauldron of Souls

Zealous Conscripts

Verdurous Gearhulk

Phyrexian Altar

How it works

1. Activate Cauldron of Souls by tapping it, giving Verdurous Gearhulk and Zealous Conscripts persist until end of turn.
2. Activate Phyrexian Altar by sacrificing Zealous Conscripts, adding one mana of any color.
3. When Zealous Conscripts dies, its persist ability triggers, returning itself from your graveyard to the battlefield with a -1/-1 counter on it.
4. When Zealous Conscripts enters the battlefield, it triggers, untapping Cauldron of Souls.
5. Activate Phyrexian Altar by sacrificing Verdurous Gearhulk, adding one mana of any color.
6. When Verdurous Gearhulk dies, its persist ability triggers, returning itself from your graveyard to the battlefield with a -1/-1 counter on it.
7. When Verdurous Gearhulk enters the battlefield, it triggers, putting a +1/+1 counter on itself and Zealous Conscripts, and two +1/+1 counters on any other creature(s) you control.
8. Repeat.

This clever loop relies on trading counters to continuously reset your creatures' mortality through Cauldron of Souls. By leveraging the mana-generating sacrifice outlet Phyrexian Altar, you can bin your threats and let their newly acquired persist triggers bring them back—Zealous Conscripts untaps the Cauldron upon re-entry to keep the engine going, while Verdurous Gearhulk distributes vital +1/+1 counters upon entering to immediately wipe away the -1/-1 counters that persist would otherwise leave behind. Because these counters cancel each other out, the cycle can repeat indefinitely, generating infinite colored mana, death triggers, and massive power across your board.