Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Geralf's Mindcrusher, and Carrion Feeder

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Geralf's Mindcrusher on the battlefield
• Carrion Feeder on the battlefield

Steps

1. Activate Carrion Feeder by sacrificing Geralf's Mindcrusher When Geralf's Mindcrusher dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
2. When Geralf's Mindcrusher enters, it triggers, causing a player to mill five cards
3. Activate Carrion Feeder by sacrificing Geralf's Mindcrusher When Geralf's Mindcrusher dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
4. When Geralf's Mindcrusher enters, it triggers, causing a player to mill five cards
5. Resolve both Carrion Feeder abilities from step 1 and 4
6. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill