Heartless Hidetsugu, and Curse of Bloodletting

Prerequisites

• Heartless Hidetsugu on the battlefield
• Curse of Bloodletting on the battlefield
• Curse of Bloodletting attached to an opponent with an even life total
• Heartless Hidetsugu does not have summoning sickness

Steps

1. Activate Heartless Hidetsugu by tapping it, causing it to deal damage to the opponent enchanted by Curse of Bloodletting equal to the opponent's life total, and to each other player equal to half their life total, rounded down
2. The opponent enchanted by Curse of Bloodletting loses the game due to having zero or less life

Results

• Near-infinite damage
• Target opponent loses the game