Stalwart Successor + Goblin Bombardment + Obstinate Gargoyle

Stalwart Successor

Goblin Bombardment

Obstinate Gargoyle

How it works

1. Activate Goblin Bombardment 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. When Obstinate Gargoyle enters, Stalwart Successor triggers, putting a +1/+1 counter on Obstinate Gargoyle
4. Resolve the Goblin Bombardment ability.
5. Repeat.