Goblin Bombardment + Lesser Masticore + Hardened Academic

Goblin Bombardment

Lesser Masticore

Hardened Academic

How it works

1. Activate Goblin Bombardment 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. Hardened Academic triggers, putting a +1/+1 counter on Lesser Masticore.
4. Resolve the Goblin Bombardment ability.
5. Repeat.