Mikaeus, the Unhallowed + Umbral Collar Zealot + Wingrattle Scarecrow

Mikaeus, the Unhallowed

Umbral Collar Zealot

Wingrattle Scarecrow

How it works

1. Activate Umbral Collar Zealot by sacrificing Wingrattle Scarecrow.
2. When Wingrattle Scarecrow dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Umbral Collar Zealot ability.
4. Activate Umbral Collar Zealot by sacrificing Wingrattle Scarecrow.
5. When Wingrattle Scarecrow dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Umbral Collar Zealot ability.
7. Repeat.

This ingenious loop relies on a brilliant mechanical tug-of-war between opposing counters to constantly recycle your sacrificial fodder through Umbral Collar Zealot. When you sacrifice Wingrattle Scarecrow, its persist ability normally brings it back with a -1/-1 counter, but Mikaeus, the Unhallowed steps in with its passive static ability to grant the Scarecrow undying as well. Because counters of opposite types annihilate each other state-based action style, the +1/+1 counter from undying and the -1/-1 counter from persist cancel each other out upon entry, leaving the Scarecrow perpetually counterless and ready to die all over again.