Narcomoeba + Mortuary + Selhoff Occultist + Yahenni, Undying Partisan

Narcomoeba

Mortuary

Selhoff Occultist

Yahenni, Undying Partisan

How it works

1. Activate Yahenni 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 Yahenni, Undying Partisan ability from step 1, giving it indestructible until end of turn.
7. Repeat.