Saffi Eriksdotter + Reveillark + Carrion Feeder

Saffi Eriksdotter

Reveillark

Carrion Feeder

How it works

1. Activate Saffi by sacrificing it, targeting Reveillark.
2. Activate Carrion Feeder by sacrificing Reveillark.
3. When Reveillark dies, it and Saffi trigger.
4. Resolve the Saffi trigger, returning Reveillark from your graveyard to the battlefield.
5. Resolve the Reveillark trigger, returning Saffi from your graveyard to the battlefield.
6. Resolve the Carrion Feeder ability from step 2, putting a +1/+1 counter on it.
7. Repeat.