Stalwart Successor + Viscera Seer + Lingering Tormentor

Stalwart Successor

Viscera Seer

Lingering Tormentor

How it works

1. Activate Viscera Seer by sacrificing Lingering Tormentor
2. When Lingering Tormentor dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Lingering Tormentor enters, Stalwart Successor triggers, putting a +1/+1 counter on Lingering Tormentor
4. Resolve the Viscera Seer ability.
5. Repeat.