Ghyrson Starn, Kelermorph, and Boros Reckoner

Prerequisites

• Ghyrson Starn, Kelermorph on the battlefield
• Boros Reckoner on the battlefield
• You have a way to deal exactly 1 damage to Boros Reckoner
• You have a way to give Boros Reckoner indestructible

Steps

1. Give Boros Reckoner indestructible, if needed, and then deal exactly 1 damage to Boros Reckoner
2. Boros Reckoner and Ghyrson Starn trigger
3. Resolve the Ghyrson Starn trigger, dealing 2 damage to Boros Reckoner
4. Boros Reckoner triggers, dealing 2 damage to any target
5. Resolve the Boros Reckoner trigger from step 2, dealing 1 damage to itself
6. Repeat from step 2

Results

• Infinite damage