Mairsil, the Pretender, Endling, Blood Vassal, and Deathbringer Thoctar

Prerequisites

• Mairsil, the Pretender on the battlefield
• Endling in exile
• Blood Vassal in exile
• Deathbringer Thoctar in exile
• Mairsil does not have a +1/+1 counter on it
• available

Steps

1. Activate Mairsil using Endling's third ability by paying , giving Mairsil undying until end of turn
2. Activate Mairsil using Blood Vassal's ability by sacrificing it, adding
3. Mairsil dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it
4. Activate Mairsil using Deathbringer Thoctar's ability by removing a +1/+1 counter from it, dealing 1 damage to any target
5. Repeat

Results

• Infinite black mana
• Infinite damage
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers