Activate Viscera Seer by sacrificing Shambling Ghast.
When Shambling Ghast dies, it and Rakdos trigger.
Resolve the Shambling Ghast trigger, creating a Treasure token.
Activate the Treasure by tapping and sacrificing it, adding .
Holding priority, activate Haunted Crossroads by paying , putting Shambling Ghast from your graveyard onto the top of your library.
Resolve the Rakdos trigger, exiling Shambling Ghast from the top of your library with the ability to cast it until your next turn.
Resolve the Viscera Seer ability, causing you to scry 1.
Cast Shambling Ghast from exile by paying 1.
Prosper triggers, creating a Treasure token.
Activate the Treasure by tapping and sacrificing it, adding 1.
Repeat.
This clever loop turns your graveyard into a workshop for endless sacrifice by weaving together sacrifice outlets and recursive value. You feed Shambling Ghast to Viscera Seer to set off a chain reaction: the Ghast leaves a Treasure behind to fund Haunted Crossroads, which conveniently places the Ghast back on top of your library. Meanwhile, Rakdos, the Muscle catches the dying creature to exile it away, allowing you to recast it and trigger Prosper, Tome-Bound for extra mana generation. The entire engine feeds on itself indefinitely, letting you sift through your library with infinite scries while generating endless storm count and death triggers.