Sister Hospitaller + Spawning Pit + Faceless Butcher

Sister Hospitaller

Spawning Pit

Faceless Butcher

How it works

1. Cast Faceless Butcher by paying its mana cost.
2. When Faceless Butcher enters, its first ability triggers, exiling Sister Hospitaller.
3. Activate Spawning Pit by sacrificing Faceless Butcher.
4. When Faceless Butcher dies, its second ability triggers, returning Sister Hospitaller from exile to the battlefield.
5. When Sister Hospitaller enters, it triggers, returning Faceless Butcher from your graveyard to the battlefield.
6. When Faceless Butcher enters, its first ability triggers, exiling Sister Hospitaller.
7. Resolve the Spawning Pit ability.
8. Repeat from step 3.