Saffi Eriksdotter + Goblin Bombardment + Metamorphosis Fanatic

Saffi Eriksdotter

Goblin Bombardment

Metamorphosis Fanatic

How it works

1. Activate Saffi by sacrificing it, targeting Metamorphosis Fanatic
2. Activate Goblin Bombardment by sacrificing Metamorphosis Fanatic
3. When Metamorphosis Fanatic dies, Saffi triggers, returning Metamorphosis Fanatic from your graveyard to the battlefield.
4. When Metamorphosis Fanatic enters, it triggers, returning Saffi from your graveyard to the battlefield.
5. Resolve the Goblin Bombardment ability.
6. Repeat.