Stalwart Successor + Altar of Dementia + Wingrattle Scarecrow

Stalwart Successor

Altar of Dementia

Wingrattle Scarecrow

How it works

1. Activate Altar of Dementia 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 Altar of Dementia ability.
5. Repeat.

This crafty loop turns Wingrattle Scarecrow into an endless mill engine by leveraging its native persist mechanic, which conveniently returns it to the battlefield with a -1/+1 neutralizing effect whenever it hits the graveyard. While that -1/-1 counter would normally spell doom for the Scarecrow, the presence of Stalwart Successor cleverly intervenes by placing a +1/+1 counter on it the first time counters are put on it each turn, which promptly cancels out the negative counter through state-based actions. With the Scarecrow's slate wiped clean on every iteration, you can repeatedly feed it to Altar of Dementia to mill your opponents out completely while generating an endless stream of death and entry triggers.