Moxite Refinery + Magistrate's Scepter + Mossborn Hydra + Selesnya Sanctuary

Moxite Refinery

Magistrate's Scepter

Mossborn Hydra

Selesnya Sanctuary

How it works

1. Play Selesnya Sanctuary. When it enters, it and Mossborn Hydra trigger.
2. Resolve the Selesnya Sanctuary 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.

By repeatedly playing and bouncing Selesnya Sanctuary to trigger Mossborn Hydra, you rapidly scale an astronomical number of +1/+1 counters onto the hydra without ever needing to cast it again. Moxite Refinery acts as your conversion engine, harvesting those surplus counters to continuously stock Magistrate's Scepter with charge counters. Once the scepter's threshold is met, you cash them in for infinite extra turns, locking your opponents out of the game entirely.