Otherworldly Escort, Amoeboid Changeling, Intruder Alarm, and Altar of Dementia

Prerequisites

• Otherworldly Escort on the battlefield
• Amoeboid Changeling on the battlefield
• Intruder Alarm on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Amoeboid Changeling's second ability by tapping it, causing Otherworldly Escort to lose all creature types until end of turn
2. Activate Altar of Dementia by sacrificing Otherworldly Escort
3. When Otherworldly Escort dies, it triggers, returning itself from your graveyard to the battlefield as a Spirit Detective
4. When Otherworldly Escort enters, Intruder Alarm triggers, untapping all creatures
5. Resolve the Altar of Dementia ability
6. Repeat

Results

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