Missy, Skirk Alarmist, Intruder Alarm, and Altar of Dementia

Prerequisites

• Missy on the battlefield
• Skirk Alarmist on the battlefield
• Intruder Alarm on the battlefield
• Altar of Dementia on the battlefield
• You control another nontoken nonartifact creature

Steps

1. Activate Altar of Dementia by sacrificing another nontoken nonartifact creature When the creature dies, Missy's first ability triggers, returning the creature from your graveyard to the battlefield face down as a 2/2 Cyberman artifact creature
2. When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures
3. Resolve the Altar of Dementia ability from step 1, causing target player to mill cards equal to the sacrificed creature's power
4. Activate Skirk Alarmist by tapping it, turning the creature face up
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mana creatures you control can produce
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill
• Infinite untap of all creatures