Cauldron of Souls + Dross Scorpion + Krark-Clan Ironworks + Biotransference

Cauldron of Souls

Dross Scorpion

Krark-Clan Ironworks

Biotransference

How it works

1. Activate Cauldron of Souls by tapping it, giving the creature with bloodthirst persist until end of turn.
2. Activate Krark-Clan Ironworks by sacrificing the creature with bloodthirst, adding CC.
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. Repeat.

This clever loop transforms ordinary creature loops into an engine of absolute recycling by turning your entire board into a machine shop. With Biotransference active, your creatures are treated as artifacts both on the battlefield and everywhere else, allowing Krark-Clan Ironworks to sacrifice them for colorelss mana while simultaneously triggering Dross Scorpion whenever an artifact creature dies. Dross Scorpion uses those deaths to continuously untap Cauldron of Souls, which in turn grants persist to your creatures so they can return to the battlefield and repeat the process. Because the sacrificed creature enters with a +1/+1 counter from its bloodthirst ability, that counter immediately cancels out the -1/-1 counter from persist, allowing the creature to survive this cycle indefinitely.