Ashnod's Altar + Harmless Offering + Karlov Watchdog + Yarus, Roar of the Old Gods

RGW identity

Commander legal

The 4 combo pieces

What must be in place

You control a face-down creature whose front face is a permanent card.
You have enough mana to cast Harmless Offering.

How to execute it

  1. Cast Harmless Offering by paying its mana cost, giving control of Karlov Watchdog to an opponent.
  2. During the opponent's turn, activate Ashnod's Altar by sacrificing a face-down creature you control, adding {C}{C}.
  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.

What the combo produces