Donna Noble, and Blazing Sunsteel

Prerequisites

• Donna Noble on the battlefield
• Blazing Sunsteel on the battlefield

Steps

1. Deal damage to the creature that has Blazing Sunsteel attached
2. Donna and Blazing Sunsteel trigger
3. Resolve the Donna trigger, dealing that much damage to an opponent
4. Resolve the Blazing Sunsteel trigger, dealing that much damage to the creature it is attached to
5. Repeat from step 2

Results

• Infinite damage