Mikaeus, the Unhallowed + Twilight Shepherd + Bloodflow Connoisseur

Mikaeus, the Unhallowed

Twilight Shepherd

Bloodflow Connoisseur

How it works

1. Activate Bloodflow Connoisseur by sacrificing Twilight Shepherd.
2. When Twilight Shepherd 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 Twilight Shepherd.
5. When Twilight Shepherd 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.