Xu-Ifit, Osteoharmonist, Intruder Alarm, and Carrion Feeder

Prerequisites

• Xu-Ifit, Osteoharmonist on the battlefield
• Intruder Alarm on the battlefield
• Carrion Feeder 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 Carrion Feeder by sacrificing the creature returned in step 1
4. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite mana creatures you control can produce
• Infinite untap of all creatures
• Infinite +1/+1 counters on Carrion Feeder