Magosi, the Waterveil + The Ozolith + Contagion Engine + Living Plane

Magosi, the Waterveil

The Ozolith

Contagion Engine

Living Plane

How it works

1. During your precombat main phase, activate Contagion Engine by paying 6 and tapping it, putting two eon counters on Magosi.
2. Activate Magosi's third ability by tapping it, removing an eon counter from it and returning it from the battlefield to your hand.
3. When Magosi leaves the battlefield, The Ozolith's first ability triggers, putting an eon counter on The Ozolith.
4. Resolve the Magosi ability, causing you to take an extra turn after this one.
5. Play Magosi.
6. At the beginning of your combat phase, The Ozolith triggers, putting two eon counters on Magosi.
7. Repeat each turn.

This brilliant setup achieves infinite turns by exploiting the way Magosi, the Waterveil tracks its own eon counters. Living Plane turns every land into a 1/1 creature, which cleverly allows Contagion Engine to target Magosi and rapidly multiply its eon counters without ever needing to skip your turns. When you bounce Magosi to take an extra turn, The Ozolith catches the disappearing eon counters and safely preserves them in exile. Finally, you replay Magosi and let The Ozolith slide those counters right back onto the land during your combat phase, looping the process endlessly.