Moxite Refinery + Magistrate's Scepter + Mossborn Hydra + Rakdos Carnarium

Moxite Refinery

Magistrate's Scepter

Mossborn Hydra

Rakdos Carnarium

How it works

1. Play Rakdos Carnarium. When it enters, it and Mossborn Hydra trigger.
2. Resolve the Rakdos Carnarium trigger, returning it from the battlefield to your hand.
3. Resolve the Mossborn Hydra trigger, doubling the number of +1/+1 counters on it.
4. Activate Moxite Refinery by paying 2, tapping it and removing three +1/+1 counters from Mossborn Hydra, putting three charge counters on Magistrate's Scepter.
5. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, causing you to take an extra turn after this one.
6. Repeat each turn.

This fascinating loop achieves infinite turns by turning the self-bouncing property of Rakdos Carnarium into an engine of exponential growth. Every time you replay the land, Mossborn Hydra's landfall ability triggers to double its massive pile of +1/+1 counters. Moxite Refinery acts as the vital conversion engine, harvesting those surplus counters to fuel Magistrate's Scepter without ever needing to spend precious mana activating the scepter's slow counter-gathering ability.