Mikaeus, the Unhallowed + Bloodied Ghost + Bloodthrone Vampire

Mikaeus, the Unhallowed

Bloodied Ghost

Bloodthrone Vampire

How it works

1. Activate Bloodthrone Vampire 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 Bloodthrone Vampire ability.
4. Repeat.
5. Activate Bloodthrone Vampire by sacrificing Bloodied Ghost.
6. When Bloodied Ghost dies, its undying ability triggers, returning it from your graveyard to the battlefield without a +1/+1 counter on it due to its replacement effect.
7. Resolve the Bloodthrone Vampire ability
8. Repeat.