Mikaeus, the Unhallowed + Viscera Seer + Kithkin Spellduster

Mikaeus, the Unhallowed

Viscera Seer

Kithkin Spellduster

How it works

1. Activate Viscera Seer by sacrificing Kithkin Spellduster.
2. When Kithkin Spellduster dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Viscera Seer ability.
4. Activate Viscera Seer by sacrificing Kithkin Spellduster.
5. When Kithkin Spellduster dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Viscera Seer ability.
7. Repeat.