Cauldron of Souls + Dross Scorpion + Arsenal Thresher + Arcbound Ravager

Cauldron of Souls

Dross Scorpion

Arsenal Thresher

Arcbound Ravager

How it works

1. Activate Cauldron of Souls by tapping it, giving Arsenal Thresher persist until end of turn.
2. Activate Arcbound Ravager 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 Arcbound Ravager ability, putting a +1/+1 counter on it.
7. Repeat.

This ingenious machinery centers on granting persist to Arsenal Thresher via Cauldron of Souls, allowing the giant construct to return from the graveyard with a -1/-1 counter. That death event triggers Dross Scorpion to untap your Cauldron, while Arsenal Thresher's own entry-replacement effect lets you reveal artifacts from your hand to place a +1/+1 counter on it, immediately neutralizing the -1/-1 counter through state-based actions. Meanwhile, Arcbound Ravager acts as the vital sacrifice outlet to keep the loop rolling whenever you need to send the Thresher back to the graveyard.