Nether Traitor | Sifter of Skulls | Pitiless Plunderer

(and one other card)

Activate
Altar of Dementia by sacrificing
Nether Traitor.
When
Nether Traitor dies,
Pitiless Plunderer and
Sifter of Skulls trigger.
Resolve the
Pitiless Plunderer trigger, creating a Treasure token.
Resolve the
Sifter of Skulls trigger, creating a 1/1 Eldrazi Scion token.
Resolve the
Altar of Dementia trigger, causing target player to mill one card.
Activate the Eldrazi Scion token by sacrificing it, adding ({C} magic symbol) .
When the Eldrazi Scion dies,
Pitiless Plunderer and
Nether Traitor trigger.
Resolve the
Pitiless Plunderer trigger, creating another Treasure token.
Activate a Treasure token by tapping and sacrificing it, adding ({B} magic symbol) .
Resolve
Nether Traitor's trigger, paying ({B} magic symbol) to return it from your graveyard to the battlefield.
Repeat.