Aetherflux Reservoir triggers, causing you to gain life.
When Acererak enters, its first ability and Carnival of Souls trigger.
Resolve the Carnival of Souls trigger, causing you to add and lose 1 life.
Resolve the Acererak trigger, returning it from the battlefield to your hand, and venturing into Lost Mine of Phandelver.
Repeat.
This clever loop hinges on Acererak the Archlich's clever design, bouncing itself straight back to your hand upon entry as long as you steer clear of the Tomb of Annihilation. Carnival of Souls plays a crucial supporting role by turning every single one of those repeat entries into the exact black mana needed to recast him, effortlessly offsetting the life drain with the help of Aetherflux Reservoir's cascading lifegain. Meanwhile, Ezzaroot Channeler works quietly behind the scenes, using that very same life buffer to completely discount Acererak's casting cost to zero, locking in an endless loop that infinitely churns through dungeons, triggers, and storm count until you have enough fuel to blast the table to oblivion.