Stalwart Successor, Thermopod, and Trapjaw Kelpie

Prerequisites

• Stalwart Successor on the battlefield
• Thermopod on the battlefield
• Trapjaw Kelpie on the battlefield

Steps

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

Results

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