Cauldron of Souls + Dross Scorpion + Encroaching Mycosynth + Bartolomé del Presidio

Cauldron of Souls

Dross Scorpion

Encroaching Mycosynth

Bartolomé del Presidio

How it works

1. Activate Cauldron of Souls by tapping it, giving the creature with bloodthirst persist until end of turn.
2. Activate Bartolomé del Presidio by sacrificing the creature with bloodthirst.
3. When the creature dies, its persist ability and Dross Scorpion trigger.
4. Resolve the persist trigger, returning the creature from your graveyard to the battlefield, which enters the battlefield with at least one +1/+1 counter on it due to its bloodthirst ability.
5. Resolve the Dross Scorpion trigger, untapping Cauldron of Souls.
6. Resolve the Bartolomé del Presidio ability, putting a +1/+1 counter on it.
7. Repeat.

This loop relies on transforming your entire board into a persistent engine using Encroaching Mycosynth, which ensures that even non-artifact creatures like your chosen threat count as artifacts. With Cauldron of Souls granting persist, you can feed that creature to Bartolomé del Presidio, whose sacrifices generate the necessary fodder while growing him larger. When the creature dies, its persist return combines with the +1/+1 counters from its bloodthirst ability to immediately negate the incoming -1/-1 counter, setting up an endless loop of sacrifices. Finally, Dross Scorpion acts as the mechanical heart of the machinery, untapping Cauldron of Souls every time an artifact creature dies so you can repeat the process indefinitely.