Ghyrson Starn, Kelermorph, Gisela, Blade of Goldnight, Helm of the Host, and Harmless Offering

Prerequisites

• Ghyrson Starn, Kelermorph on the battlefield
• Gisela, Blade of Goldnight on the battlefield
• Helm of the Host on the battlefield
• Harmless Offering in hand
• You have a way to deal exactly two or three damage to an opponent
• You have enough mana to cast Harmless Offering
• Helm of the Host attached to Ghyrson Starn

Steps

1. Cast Harmless Offering by paying its mana cost, giving control of Gisela to an opponent
2. At the beginning of your combat phase, Helm of the Host triggers, 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