Goblin Bombardment + Thran Vigil + Grazing Kelpie

Goblin Bombardment

Thran Vigil

Grazing Kelpie

How it works

1. Activate Goblin Bombardment by sacrificing Grazing Kelpie.
2. When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Thran Vigil triggers, putting a +1/+1 counter on Grazing Kelpie.
4. Resolve the Goblin Bombardment ability.
5. Repeat.