Stalwart Successor, Ashnod's Altar, and Lingering Tormentor

Prerequisites

• Stalwart Successor on the battlefield
• Ashnod's Altar on the battlefield
• Lingering Tormentor on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Lingering Tormentor When Lingering Tormentor dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
2. When Lingering Tormentor enters, Stalwart Successor triggers, putting a +1/+1 counter on Lingering Tormentor Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite colorless mana
• Infinite death triggers
• Infinite sacrifice triggers