Chainer, Dementia Master, K'rrik, Son of Yawgmoth, Gray Merchant of Asphodel, and Carrion Feeder

Prerequisites

• Chainer, Dementia Master on the battlefield
• K'rrik, Son of Yawgmoth on the battlefield
• Gray Merchant of Asphodel on the battlefield
• Carrion Feeder on the battlefield
• Your life total is at least ten
• Your devotion to black is at least ten or you have at least two opponents

Steps

1. Activate Carrion Feeder by sacrificing Gray Merchant, putting a +1/+1 counter on it
2. Activate Chainer by paying nine life, returning Gray Merchant from your graveyard to the battlefield as a Nightmare in addition to its other creature types
3. Gray Merchant enters the battlefield, causing each opponent to lose life equal to your devotion to black and causing you to gain life equal to the amount of life lost this way
4. Repeat

Results

• Infinite +1/+1 counters on Carrion Feeder
• Infinite death triggers
• Infinite ETB
• Infinite lifegain
• Infinite lifegain triggers
• Infinite lifeloss
• Infinite LTB
• Infinite sacrifice triggers
• Put all creature cards from all graveyards onto the battlefield under your control