Activate Shilgengar by sacrificing Cult Conscript.
When Cult Conscript dies, Pitiless Plunderer and Magus of the Bridge trigger, creating a creature token and a Treasure token.
Resolve the Shilgengar ability.
Activate Shilgengar by sacrificing the creature token.
When the creature token dies, Pitiless Plunderer triggers, creating a Treasure token.
Resolve the Shilgengar ability.
Activate the Treasures by tapping and sacrificing them, adding 1.
Activate Cult Conscript by paying 1, returning it from your graveyard to the battlefield.
Repeat.
This ingenious recycling engine puts Shilgengar, Sire of Famine at the center of a self-sustaining cycle by leveraging Pitiless Plunderer to turn every death into the mana required to loop your fodder. When you sacrifice Cult Conscript to Shilgengar, the Plunderer provides the necessary Treasure and Magus of the Bridge spawns a Zombie token to keep the sacrifices flowing. Because Cult Conscript's own ability can be activated as long as a non-Skeleton creature died under your control this turn, the mana from those Treasures effortlessly pays to bring it right back from the graveyard for another round.