Blazing Sunsteel, and Clever Impersonator

Prerequisites

• Blazing Sunsteel on the battlefield
• Clever Impersonator on the battlefield
• Blazing Sunsteel and Clever Impersonator attached to an indestructible creature you control
• You have a way to deal damage to the indestructible creature

Steps

1. Deal damage to the indestructible creature
2. Blazing Sunsteel and Clever Impersonator trigger
3. Resolve the Blazing Sunsteel trigger, dealing damage equal to the damage dealt to any target
4. Resolve the Clever Impersonator trigger, dealing damage equal to the damage dealt to the indestructible creature
5. Repeat from step 2

Results

• Infinite damage