Abhorrent Overlord, Nim Deathmantle, and Ashnod's Altar

Prerequisites

• Abhorrent Overlord on the battlefield
• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Nim Deathmantle attached to Abhorrent Overlord
• available

Steps

1. Activate Ashnod's Altar by sacrificing Abhorrent Overlord, adding
2. Abhorrent Overlord dies, triggering Nim Deathmantle, causing you to pay to return Abhorrent Overlord from your graveyard to the battlefield, and attach Nim Deathmantle to it
3. Abhorrent Overlord enters the battlefield, creating a number of 1/1 Harpy creature tokens equal to your devotion to black
4. Activate Ashnod's Altar by sacrificing a Harpy, adding
5. Repeat

Results

• Infinite colorless mana
• Infinite creature tokens
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers