Mikaeus, the Unhallowed, Thermopod, and Pith Driller

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Thermopod on the battlefield
• Pith Driller on the battlefield

Steps

1. Activate Thermopod's second ability by sacrificing Pith Driller, adding
2. When Pith Driller dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it
3. When Pith Driller enters the battlefield, it triggers, putting a -1/-1 counter on it
4. Repeat

Results

• Infinite death triggers
• Infinite creature ETB
• Infinite creature LTB
• Infinite red mana
• Infinite creature sacrifice triggers