Yarus, Roar of the Old Gods, Karlov Watchdog, Ashnod's Altar, and Iroh, Tea Master

Prerequisites

• Yarus, Roar of the Old Gods on the battlefield
• Karlov Watchdog on the battlefield
• Ashnod's Altar on the battlefield
• Iroh, Tea Master on the battlefield

Steps

1. Donate Karlov Watchdog to an opponent
2. During the opponent's turn, activate Ashnod's Altar by sacrificing a face-down creature you control
3. When the creature dies, Yarus's second ability triggers, returning it from your graveyard to the battlefield face-down as a 2/2 creature, and then not turning it face-up due to Karlov Watchdog
4. Repeat from step 2

Results

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