Guilty Conscience, Boros Reckoner, and Indestructibility

Prerequisites

• Guilty Conscience on the battlefield
• Boros Reckoner on the battlefield
• Indestructibility on the battlefield
• Indestructibility and Guilty Conscience attached to Boros Reckoner
• Boros Reckoner does not have summoning sickness

Steps

1. Attack with Boros Reckoner
2. When Boros Reckoner deals damage, Guilty Conscience triggers, dealing damage to Boros Reckoner equal to the amount of damage Boros Reckoner dealt
3. Boros Reckoner triggers, dealing damage equal to the amount of damage Guilty Conscience dealt to it to any target
4. Repeat from step 2

Results

• Infinite damage
• Infinite lifegain
• Infinite lifegain triggers