Infinite turns, Lock
Cast Time Stretch by paying , causing you to take two extra turns after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Time Stretch from your graveyard.
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.
Reso
Component Cards
How It Works
Cast Time Stretch by paying , causing you to take two extra turns after this one.
At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Izzet Chemister.
Activate the Izzet Chemister token's first ability by paying and tapping it, exiling Time Stretch from your graveyard.
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.
Resolve that spell, causing you to take two extra turns after this one.
Repeat from step 2 (note that you may divide these steps among your multiple extra turns to reduce the mana requirements down to the amount shown in the prerequisites).