Xu-Ifit, Osteoharmonist, Intruder Alarm, and Altar of Dementia

Prerequisites

• Xu-Ifit, Osteoharmonist on the battlefield
• Intruder Alarm on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Xu-Ifit by tapping it, returning a creature card from your graveyard to the battlefield
2. When the creature enters the battlefield, Intruder Alarm triggers, untapping all creatures
3. Activate Altar of Dementia by sacrificing the creature returned in step 1
4. 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 creatures