Mikaeus, the Unhallowed + Wingrattle Scarecrow + Bloodflow Connoisseur

Mikaeus, the Unhallowed

Wingrattle Scarecrow

Bloodflow Connoisseur

How it works

1. Activate Bloodflow Connoisseur 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 Bloodflow Connoisseur ability.
4. Activate Bloodflow Connoisseur 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 Bloodflow Connoisseur ability.
7. Repeat.