Blazing Sunsteel, and Wrathful Red Dragon

Prerequisites

• Blazing Sunsteel on the battlefield
• Wrathful Red Dragon on the battlefield

Steps

1. Deal damage to Wrathful Red Dragon
2. Wrathful Red Dragon and Blazing Sunsteel trigger
3. Resolve the Wrathful Red Dragon trigger, dealing damage to any target that isn't a Dragon
4. Resolve the Blazing Sunsteel trigger, dealing damage to Wrathful Red Dragon
5. Repeat from step 2

Results

• Infinite damage