Spawning Pit + Wormfang Drake + Metamorphosis Fanatic

Spawning Pit

Wormfang Drake

Metamorphosis Fanatic

How it works

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