Activate Viscera Seer by sacrificing Oathsworn Vampire.
When Oathsworn Vampire dies, Pitiless Plunderer and Pawn of Ulamog trigger.
Resolve the Pitiless Plunderer trigger, creating a Treasure artifact token.
Resolve the Pawn of Ulamog trigger, creating a 0/1 Eldrazi Spawn creature token.
Resolve the Viscera Seer ability, causing you to scry 1.
Activate the Treasure by tapping and sacrificing it, adding ({B} magic symbol) .
Activate the Eldrazi Spawn by sacrificing it, adding ({C} magic symbol) .
When the Eldrazi Spawn dies, Pitiless Plunderer triggers, creating a Treasure token.
Cast Oathsworn Vampire from your graveyard by paying ({1} magic symbol) ({B} magic symbol) .
Repeat any number of times.
Once you have infinite Treasure tokens, you may repeat this loop spending mana from Treasures instead of Eldrazi Spawns in step 7, giving you infinite Eldrazi Spawn tokens.