Izzet Chemister, Helm of the Host, and Time Walk

Prerequisites

• Izzet Chemister on the battlefield
• Helm of the Host on the battlefield
• Time Walk in hand
• Helm of the Host attached to Izzet Chemister
• available the first turn, with each extra turn available

Steps

1. Cast Time Walk by paying , causing you to take an extra turn after this one
2. At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister
3. Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Time Walk from your graveyard
4. On your next turn, activate the Izzet Chemister token's last ability by paying , tapping it, and sacrificing it, casting the exiled spell without paying its mana cost
5. Resolve that spell, causing you to take an extra turn after this one
6. Repeat from step 2

Results

• Infinite turns