Yarus, Roar of the Old Gods + Karlov Watchdog + Stiltzkin, Moogle Merchant + Phantom Train

Yarus, Roar of the Old Gods

Karlov Watchdog

Stiltzkin, Moogle Merchant

Phantom Train

How it works

1. Donate Karlov Watchdog to an opponent.
2. During the opponent's turn, activate Phantom Train 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. Resolve the Phantom Train ability.
5. Repeat from step 2.

This clever loop leverages the unique interaction between Yarus, Roar of the Old Gods and Karlov Watchdog to farm infinite sacrifice and death triggers. By donating Karlov Watchdog to your opponent via Stiltzkin, Moogle Merchant, you ensure that any face-down creature returning from your graveyard is permanently trapped in its face-down state, ready to be repeatedly fed to Phantom Train. Whenever you sacrifice a face-down creature to fuel Phantom Train's growth, Yarus, Roar of the Old Gods immediately revives it back to the battlefield face down, bypassing its usual face-up reveal because Karlov Watchdog's static ability forbids opponents' permanents from turning face up during your turn.