Mikaeus, the Unhallowed, Rise of the Dark Realms, Ashnod's Altar, Blood Pet, and Ardent Elementalist

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Rise of the Dark Realms in hand
• Ashnod's Altar on the battlefield
• Blood Pet on the battlefield
• Ardent Elementalist on the battlefield
• Blood Pet does not have a +1/+1 counter on it
• You control another nontoken non-Human creature that does not have a +1/+1 counter on it

Steps

1. Activate Blood Pet by sacrificing it, adding
2. When Blood Pet dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it
3. Activate Blood Pet by sacrificing it, adding
4. Activate Ashnod's Altar twice by sacrificing Ardent Elementalist and another nontoken non-Human creature, adding
5. When the non-Human creature dies, its undying ability triggers, returning it to the battlefield from your graveyard with a +1/+1 counter on it
6. Activate Ashnod's Altar twice by sacrificing Mikaeus and the non-Human creature, adding
7. Cast Rise of the Dark Realms by paying , putting all creature cards from all graveyards onto the battlefield under your control
8. When Ardent Elementalist enters the battlefield, it triggers, returning Living Death to your hand from your graveyard
9. Repeat

Results

• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite magecraft triggers
• Infinite sacrifice triggers
• Infinite storm count