Stalwart Successor + Umbral Collar Zealot + Lesser Masticore

Stalwart Successor

Umbral Collar Zealot

Lesser Masticore

How it works

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