Mikaeus, the Unhallowed + Bloodied Ghost + Bloodflow Connoisseur

Mikaeus, the Unhallowed

Bloodied Ghost

Bloodflow Connoisseur

How it works

1. Activate Bloodflow Connoisseur by sacrifiicing Bloodied Ghost.
2. When Bloodied Ghost dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it. When it enters, Bloodied Ghost will put a -1/-1 counter on itself, removing the +1/+1 counter.
3. Resolve the Bloodflow Connoisseur ability.
4. Repeat.