Mikaeus, the Unhallowed + Viscera Seer + Putrid Goblin

Mikaeus, the Unhallowed

Viscera Seer

Putrid Goblin

How it works

1. Activate Viscera Seer by sacrificing Putrid Goblin.
2. When Putrid Goblin 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 Putrid Goblin.
5. When Putrid Goblin 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.