Chainer, Dementia Master, K'rrik, Son of Yawgmoth, Gray Merchant of Asphodel, and Blasting Station

Prerequisites

• Chainer, Dementia Master on the battlefield
• K'rrik, Son of Yawgmoth on the battlefield
• Gray Merchant of Asphodel on the battlefield
• Blasting Station on the battlefield

Steps

1. Activate Blasting Station by tapping it and sacrificing Gray Merchant
2. Activate Chainer by paying 9 life due to K'rrik, returning Gray Merchant from your graveyard to the battlefield as a Nightmare in addition to its other creature types
3. When Gray Merchant enters, it and Blasting Station trigger
4. Resolve the Gray Merchant trigger, causing each opponent to lose life equal to your devotion to black and causing you to gain that much life
5. Resolve the Blasting Station trigger, untapping it
6. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite damage
• Infinite death triggers
• Infinite lifegain
• Infinite lifegain triggers
• Infinite lifeloss
• Infinite sacrifice triggers
• Return all creature cards from all graveyards to the battlefield under your control
• Infinite mana creatures you control can produce
• Infinite untap of creatures you control