Thermopod, Trapjaw Kelpie, and Hardened Academic

Prerequisites

• Thermopod on the battlefield
• Trapjaw Kelpie on the battlefield
• Hardened Academic on the battlefield

Steps

1. Activate Thermopod by sacrificing Trapjaw Kelpie
2. When Trapjaw Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Hardened Academic triggers, putting a +1/+1 counter on Trapjaw Kelpie
4. Repeat

Results

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