Activate Altar of Dementia twice by sacrificing a nontoken creature you control and Slimefoot and Squee.
When the creatures die, Pitiless Plunderer triggers twice, creating two Treasure artifact tokens.
Resolve the Altar of Dementia abilities, causing target player to mill cards equal to the sacrificed creatures' powers.
Activate the Treasures by tapping and sacrificing them, adding two of , or .
Activate Slimefoot and Squee by paying 1 and sacrificing a Saproling.
When the Saproling dies, Pitiless Plunderer triggers, creating a Treasure artifact token.
Resolve the Slimefoot and Squee ability, returning it and another creature from your graveyard to the battlefield.
When Slimefoot and Squee enter the battlefield, it triggers, creating a 1/1 Saproling creature token.
Activate the Treasure by tapping and sacrificing it, adding .
Repeat.
This vicious recycling loop hinges on Slimefoot and Squee acting as both a recurring threat and a factory for fodder, bringing back a lost friend from the graveyard while leaving a Saproling token behind on arrival. Pitiless Plunderer quietly watches the carnage, turning every single creature death into a pristine Treasure token to fund the operation. Meanwhile, Goldspan Dragon doubles the output of those very Treasures, ensuring you generate an excess of mana with every cycle. Finally, Altar of Dementia capitalizes on the revolving door of bodies by forcing your opponent to mill their entire library away one sacrifice at a time.