Ghyrson Starn, Kelermorph, Gisela, Blade of Goldnight, Irenicus's Vile Duplication, and Zedruu the Greathearted

Prerequisites

• Ghyrson Starn, Kelermorph on the battlefield
• Gisela, Blade of Goldnight on the battlefield
• Irenicus's Vile Duplication on the battlefield
• Zedruu the Greathearted on the battlefield
• You have a way to deal exactly two or three damage to an opponent
• You have enough mana to cast Irenicus's Vile Duplication

Steps

1. Activate Zedruu by paying , giving control of Gisela to an opponent
2. Cast Irenicus's Vile Duplication by paying its mana cost, creating a token copy of Ghyrson Starn that isn't legendary
3. Deal exactly two or three damage to the opponent, which is reduced to one by Gisela, triggering Ghyrson Starn and the Ghyrson Starn token
4. Resolve the nontoken Ghyrson Starn's trigger, dealing 1 damage to the opponent
5. The token Ghyrson Starn triggers, dealing 1 damage to the opponent
6. The nontoken Ghyrson Starn triggers, dealing 1 damage to the opponent
7. Repeat from step 5

Results

• Infinite damage to target opponent