Mikaeus, the Unhallowed + Sarcatog + Grim Poppet

Mikaeus, the Unhallowed

Sarcatog

Grim Poppet

How it works

1. Activate Sarcatog 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 Sarcatog ability
4. Repeat.

This clever loop turns Mikaeus, the Unhallowed into an engine of endless rebirth, granting its passive undying buff to non-Human creatures like Grim Poppet. When you feed that Grim Poppet to Sarcatog's sacrifice ability, Mikaeus triggers to return the Poppet straight back to the battlefield with a fresh slate. Because Sarcatog's activation allows you to loop this sacrifice infinitely, you generate an endless stream of deaths and triggers while pumping the Sarcatog to astronomical proportions.