Magosi, the Waterveil, Lithoform Engine, and Tidewater Minion

Prerequisites

• Magosi, the Waterveil on the battlefield
• Lithoform Engine on the battlefield
• Tidewater Minion on the battlefield
• each turn available

Steps

1. Activate Magosi's second activated ability by paying and tapping it, putting an eon counter on Magosi and skipping your next turn
2. Activate Tidewater Minion by tapping it, untapping Magosi
3. Activate Magosi's third activated ability by tapping it, removing an eon counter from it, and returning it to your hand
4. Holding priority, activate Lithoform Engine by paying and tapping it, copying Magosi's ability
5. Resolve both instances of Magosi's ability, causing you to take two extra turns after this one
6. Play Magosi
7. Move to your second extra turn
8. The first extra turn will be skipped due to the ability activated in step 1
9. Repeat

Results

• Infinite turns
• Lock