Stalwart Successor + Sarcatog + Wingrattle Scarecrow

Stalwart Successor

Sarcatog

Wingrattle Scarecrow

How it works

1. Activate Sarcatog 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. When Wingrattle Scarecrow enters, Stalwart Successor triggers, putting a +1/+1 counter on Wingrattle Scarecrow
4. Resolve the Sarcatog ability.
5. Repeat.

This clever loop relies on Sarcatog as the sacrifice outlet to continually send Wingrattle Scarecrow to the graveyard, triggering its persist ability to return it with a -1/-1 counter. Because the persist return makes Wingrattle Scarecrow enter the graveyard and then the battlefield, it sets off Stalwart Successor's triggered ability to place a +1/+1 counter on it for the first counters put on it that turn. State-based actions then cause the +1/+1 counter and the -1/-1 counter to annihilate each other, leaving the Scarecrow clean of counters so the whole sequence can repeat endlessly.