Overseer of the Damned, Dictate of Erebos, and Altar of Dementia

Prerequisites

• Overseer of the Damned on the battlefield
• Dictate of Erebos on the battlefield
• Altar of Dementia on the battlefield
• You control at least one additional creature

Steps

1. Activate Altar of Dementia by sacrificing any other creature
2. Dictate of Erebos triggers, causing each opponent to sacrifice a creature
3. Overseer of the Damned triggers, creating a 2/2 Zombie creature token for each creature sacrificed
4. Resolve the Altar of Dementia trigger, causing target player to mill cards equal to the sacrificed creature's power
5. Repeat
6. You may also repeat this loop any time a creature enters the battlefield under an opponent control

Results

• Cause each opponent to sacrifice any creature that enters the battlefield under their control
• Each opponent sacrifices all creatures they control