Saffi Eriksdotter + Umbral Collar Zealot + Metamorphosis Fanatic

Saffi Eriksdotter

Umbral Collar Zealot

Metamorphosis Fanatic

How it works

1. Activate Saffi by sacrificing it, targeting Metamorphosis Fanatic
2. Activate Umbral Collar Zealot 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 Umbral Collar Zealot ability.
6. Repeat.