Wingrattle Scarecrow + Carrion Feeder + Hardened Academic

Wingrattle Scarecrow

Carrion Feeder

Hardened Academic

How it works

1. Activate Carrion Feeder 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. Hardened Academic triggers, putting a +1/+1 counter on Wingrattle Scarecrow.
4. Resolve the Carrion Feeder ability.
5. Repeat.

This crafty loop centers on Carrion Feeder hungrily consuming Wingrattle Scarecrow, which constantly returns from the graveyard thanks to its persist ability granting it a fresh lease on life whenever it perches with a black creature. Because Wingrattle Scarecrow leaves the graveyard during this cycle, Hardened Academic's clever triggered ability swoops in to place a +1/+1 counter on the Scarecrow right as it returns. State-based actions immediately cause that new +1/+1 counter and the persist -1/-1 counter to annihilate each other, leaving Wingrattle Scarecrow entirely clean of counters and ready to be sacrificed all over again.