Narcomoeba + Mortuary + Selhoff Occultist + Carrion Feeder

Narcomoeba

Mortuary

Selhoff Occultist

Carrion Feeder

How it works

1. Activate Carrion Feeder by sacrificing Narcomoeba.
2. When Narcomoeba dies, Selhoff Occultist and Mortuary trigger.
3. Resolve the Mortuary trigger, putting Narcomoeba from your graveyard on top of your library.
4. Resolve the Selhoff Occultist trigger, causing you to mill Narcomoeba from the top of your library.
5. Narcomoeba triggers, putting it from your graveyard onto the battlefield.
6. Resolve the Carrion Feeder ability from step 1, putting a +1/+1 counter on it.
7. Repeat.