Dualcaster Mage, Second Sunrise, and Altar of Dementia

Prerequisites

• Dualcaster Mage in hand
• Second Sunrise in hand
• Altar of Dementia on the battlefield
• available

Steps

1. Cast Second Sunrise by paying
2. Holding priority, cast Dualcaster Mage by paying
3. Dualcaster Mage enters the battlefield, copying Second Sunrise
4. Holding priority, activate Altar of Dementia by sacrificing Dualcaster Mage, causing target player to mill cards equal to Dualcaster Mage's power
5. Resolve the Second Sunrise copy, returning permanents that was put in your graveyard this turn to the battlefield
6. Repeat from step 3

Results

• Infinite ETB
• Infinite LTB
• Infinite mill
• Infinite sacrifice triggers