Umbral Collar Zealot + Hardened Academic + Obstinate Gargoyle

Umbral Collar Zealot

Hardened Academic

Obstinate Gargoyle

How it works

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