Stalwart Successor, Krark-Clan Ironworks, and Wingrattle Scarecrow

Prerequisites

• Stalwart Successor on the battlefield
• Krark-Clan Ironworks on the battlefield
• Wingrattle Scarecrow on the battlefield

Steps

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

Results

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