Pitiless Plunderer + Eternal Witness + Mitotic Slime + Nethroi, Apex of Death + Altar of Dementia

Pitiless Plunderer

Eternal Witness

Mitotic Slime

Nethroi, Apex of Death

Altar of Dementia

How it works

1. Cast Nethroi either from your hand or from the command zone for its mutate cost by paying 4G/W plus commander tax, if applicable, putting it on top of a non-Human creature you control.
2. When Nethroi enters the battlefield, it triggers.
3. Holding priority, activate Altar of Dementia by sacrificing Nethroi.
4. When Nethroi dies, Pitiless Plunderer triggers, creating a Treasure artifact token.
5. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Nethroi's power.
6. Resolve the Nethroi trigger from step 2, returning Eternal Witness and Mitotic Slime from your graveyard to the battlefield.
7. When Eternal Witness enters the battlefield, it triggers, returning Nethroi from your graveyard to your hand.
8. Activate Altar of Dementia twice by sacrificing Eternal Witness and Mitotic Slime.
9. When Eternal Witness and Mitotic Slime die, Pitiless Plunderer triggers twice and Mitotic Slime triggers once.
10. Resolve both Pitiless Plunderer triggers, creating two Treasure artifact tokens.
11. Resolve the Mitotic Slime trigger, creating two 2/2 Ooze creature tokens.
12. Resolve both Altar of Dementia abilities, causing target player to mill cards equal to Eternal Witness and Mitotic Slime's combined power.
13. Activate Altar of Dementia twice by sacrificing two Oozes.
14. When the Oozes die, they each trigger and Pitiless Plunderer triggers twice.
15. Resolve both Pitiless Plunderer triggers, creating two Treasure artifact tokens.
16. Resolve both Ooze triggers, creating four 1/1 Ooze creature tokens.
17. Resolve both Altar of Dementia abilities, causing target player to mill cards equal to the Ooze's combined power.
18. Activate Altar of Dementia twice by sacrificing two Oozes.
19. When the Oozes die, Pitiless Plunderer triggers twice, creating two Treasure artifact tokens.
20. Resolve both Altar of Dementia abilities, causing target player to mill cards equal to the Ooze's combined power.
21. Activate the seven Treasures by tapping and sacrificing them, adding 4G/W.
22. Repeat.

This intricate loop kicks off when you mutate Nethroi, Apex of Death onto a creature and immediately feed it to Altar of Dementia, triggering Nethroi's massive graveyard recursion. As Nethroi hits the graveyard, Pitiless Plunderer watches from the battlefield to generate a Treasure token for every creature that subsequently perishes. Nethroi's recursion brings back Eternal Witness—which loops Nethroi right back to your hand—alongside Mitotic Slime. The Slime's successive generations of dying tokens feed Altar of Dementia and produce a cascade of extra death triggers for Pitiless Plunderer, ultimately netting you an excess of mana and fuel to repeat the entire cycle endlessly.