Moxite Refinery + Magistrate's Scepter + Mossborn Hydra + Golgari Rot Farm

Moxite Refinery

Magistrate's Scepter

Mossborn Hydra

Golgari Rot Farm

How it works

1. Play Golgari Rot Farm. When it enters, it and Mossborn Hydra trigger.
2. Resolve the Golgari Rot Farm 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 clever loop harnesses the repeatable landfall trigger of Mossborn Hydra by continually replaying and bouncing Golgari Rot Farm, which geometrically escalates the Hydra's +1/+1 counters each turn. With those accumulated counters serving as a renewable resource, Moxite Refinery can safely convert them into the charge counters needed to fuel Magistrate's Scepter's extra-turn ability. Once this engine is running, you secure infinite turns to dominate the board completely.