Blazing Sunsteel, and Screaming Nemesis

Prerequisites

• Blazing Sunsteel on the battlefield
• Screaming Nemesis on the battlefield

Steps

1. Deal damage to Screaming Nemesis
2. Screaming Nemesis and Blazing Sunsteel trigger
3. Resolve the Screaming Nemesis trigger, dealing damage to any target
4. Resolve the Blazing Sunsteel trigger, dealing damage to Screaming Nemesis
5. Repeat from step 2

Results

• Infinite damage
• Opponents can't gain life for the rest of the game