Cauldron of Souls + Dross Scorpion + Arsenal Thresher + Bloodflow Connoisseur

Cauldron of Souls

Dross Scorpion

Arsenal Thresher

Bloodflow Connoisseur

How it works

1. Activate Cauldron of Souls by tapping it, giving Arsenal Thresher persist until end of turn.
2. Activate Bloodflow Connoisseur by sacrificing Arsenal Thresher.
3. When Arsenal Thresher dies, its persist ability and Dross Scorpion trigger.
4. Resolve the Dross Scorpion trigger, untapping Cauldron of Souls.
5. Resolve the Arsenal Thresher trigger, returning it from your graveyard to the battlefield with a -1/-1 counter on it, and then choosing to reveal at least one artifact card from your hand to remove the -1/-1 counter.
6. Resolve the Bloodflow Connoisseur ability, putting a +1/+1 counter on it.
7. Repeat.

This crafty loop turns Cauldron of Souls into an engine for endless recycling by granting persist to Arsenal Thresher, allowing it to slip right back onto the battlefield whenever it perishes. As that artifact creature dies, Dross Scorpion springs into action to untap the Cauldron, keeping your magical machinery ready for another round. Meanwhile, Bloodflow Connoisseur provides the willing sacrifice outlet to send the Thresher away, growing larger with a +1/+1 counter every single time the cycle repeats.