Mikaeus, the Unhallowed + Grim Poppet + Arcbound Ravager

Mikaeus, the Unhallowed

Grim Poppet

Arcbound Ravager

How it works

1. Activate Arcbound Ravager by sacrificing Grim Poppet.
2. When Grim Poppet dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
3. Resolve the Arcbound Ravager ability
4. Repeat.

Mikaeus, the Unhallowed anchors this entire engine by granting every non-Human creature you control the undying ability, which allows them to return from the graveyard with a +1/+1 counter whenever they die without one. Grim Poppet takes full advantage of this by entering the battlefield to absorb the undying cycle while utilizing its own ability to remove -1/-1 counters, though here it simply serves as the disposable sacrifice. By feeding Grim Poppet to Arcbound Ravager's activation cost, you send the Poppet to the graveyard to trigger Mikaeus, the Unhallowed's resurrection while the Ravager grows larger and prepares to receive future modular counters.