Mikaeus, the Unhallowed + Goblin Bombardment + Rendclaw Trow

Mikaeus, the Unhallowed

Goblin Bombardment

Rendclaw Trow

How it works

1. Activate Goblin Bombardment by sacrificing Rendclaw Trow.
2. When Rendclaw Trow dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. Resolve the Goblin Bombardment ability.
4. Activate Goblin Bombardment by sacrificing Rendclaw Trow.
5. When Rendclaw Trow dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
6. Resolve the Goblin Bombardment ability.
7. Repeat.