Requires

Eternal Witness must be in the graveyard. Sevinne's Reclamation must be in hand. Phyrexian Altar must be on the battlefield. Pitiless Plunderer must be on the battlefield. Pawn of Ulamog must be on the battlefield. Mana needed:

Steps

1. Cast Sevinne's Reclamation by paying , returning Eternal Witness to the battlefield.
2. Eternal Witness enters the battlefield, returning Sevinne's Reclamation from your graveyard to your hand.
3. Activate Phyrexian Altar by sacrificing Eternal Witness, adding .
4. Pitiless Plunderer and Pawn of Ulamog triggers.
5. Resolve the Pitiless Plunderer, creating a Treasure token.
6. Resolve the Pawn of Ulamog trigger, creating a 0/1 Eldrazi Spawn creature token.
7. Activate a Treasure token by tapping and sacrificing it, adding one mana of any color.
8. Activate Eldrazi Spawn by sacrificing it, adding .
9. Pitiless Plunderer triggers, creating a Treasure token.
10. Repeat any number of times.
11. Once you have infinite Treasure tokens, you may repeat this loop spending mana from Treasures instead of Eldrazi Spawns in step 8, giving you infinite Eldrazi Spawn tokens.

Results