Activate Phyrexian Altar twice by sacrificing Mitotic Slime and Eternal Witness, adding {W}{W}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {G}{G}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {B}{B}{B}.
Cast Eerie Ultimatum by paying {W}{W}{B}{B}{B}{G}{G}, returning Eternal Witness and Mitotic Slime to the battlefield from your graveyard.
When Eternal Witness enters the battlefield, it triggers, returning Eerie Ultimatum from your graveyard to your hand.
Repeat.

Infinite colored mana

Infinite creature tokens

Infinite death triggers

Infinite creature ETB

Infinite creature LTB

Infinite magecraft triggers

Infinite creature sacrifice triggers

Infinite storm count

Eerie Ultimatum

Mitotic Slime

Phyrexian Altar

Eternal Witness

Activate Phyrexian Altar twice by sacrificing Mitotic Slime and Timeless Witness, adding {W}{W}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {G}{G}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {B}{B}{B}.
Cast Eerie Ultimatum by paying {W}{W}{B}{B}{B}{G}{G}, returning Timeless Witness and Mitotic Slime to the battlefield from your graveyard.
When Timeless Witness enters the battlefield, it triggers, returning Eerie Ultimatum from your graveyard to your hand.
Repeat.

Timeless Witness

Activate Phyrexian Altar twice by sacrificing Mitotic Slime and Mnemonic Wall, adding {W}{W}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {G}{G}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {B}{B}{B}.
Cast Eerie Ultimatum by paying {W}{W}{B}{B}{B}{G}{G}, returning Mnemonic Wall and Mitotic Slime to the battlefield from your graveyard.
When Mnemonic Wall enters the battlefield, it triggers, returning Eerie Ultimatum from your graveyard to your hand.
Repeat.

Mnemonic Wall

Activate Phyrexian Altar twice by sacrificing Mitotic Slime and Shipwreck Dowser, adding {W}{W}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {G}{G}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {B}{B}{B}.
Cast Eerie Ultimatum by paying {W}{W}{B}{B}{B}{G}{G}, returning Shipwreck Dowser and Mitotic Slime to the battlefield from your graveyard.
When Shipwreck Dowser enters the battlefield, it triggers, returning Eerie Ultimatum from your graveyard to your hand.
Repeat.

Shipwreck Dowser

Activate Phyrexian Altar twice by sacrificing Mitotic Slime and Salvager of Secrets, adding {W}{W}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {G}{G}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {B}{B}{B}.
Cast Eerie Ultimatum by paying {W}{W}{B}{B}{B}{G}{G}, returning Salvager of Secrets and Mitotic Slime to the battlefield from your graveyard.
When Salvager of Secrets enters the battlefield, it triggers, returning Eerie Ultimatum from your graveyard to your hand.
Repeat.

Salvager of Secrets

Activate Phyrexian Altar twice by sacrificing Mitotic Slime and Archaeomancer, adding {W}{W}.
When Mitotic Slime dies, it triggers, creating two 2/2 Ooze creature tokens.
Activate Phyrexian Altar twice by sacrificing the Oozes, adding {G}{G}.
When the Oozes die, they trigger, creating four 1/1 Ooze creature tokens.
Activate Phyrexian Altar three times by sacrificing three Oozes, adding {B}{B}{B}.
Cast Eerie Ultimatum by paying {W}{W}{B}{B}{B}{G}{G}, returning Archaeomancer and Mitotic Slime to the battlefield from your graveyard.
When Archaeomancer enters the battlefield, it triggers, returning Eerie Ultimatum from your graveyard to your hand.
Repeat.

Combos with "Eerie Ultimatum"