Eternal Scourge, Pawn of Ulamog, Nightmare Shepherd, and Ashnod's Altar

Prerequisites

• All permanents on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Eternal Scourge, adding
2. Nightmare Shepherd and Pawn of Ulamog triggers
3. Resolve the Nightmare Shepherd trigger, exiling Eternal Scourge from your graveyard and creating a 1/1 copy of Eternal Scourge that is a Nightmare in addition to its other types
4. Resolve the Pawn of Ulamog trigger, creating a 0/1 Eldrazi Spawn creature token
5. Activate Ashnod's Altar by sacrificing either token, adding
6. Cast Eternal Scourge from exile by paying
7. Repeat

Results

• Infinite creature tokens
• Infinite colorless mana
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers
• Infinite storm count