Gravespawn Sovereign, Bile Urchin, and Intruder Alarm

Prerequisites

• Gravespawn Sovereign on the battlefield
• Bile Urchin on the battlefield
• Intruder Alarm on the battlefield
• At least four other Zombies on the battlefield

Steps

1. Sacrifice Bile Urchin to have target opponent lose 1 life
2. Tap 5 untapped zombies you control to return Bile Urchin to the battlefield
3. Intruder Alarm triggers, untapping all creatures
4. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite lifeloss
• Infinite LTB