Ashaya, Soul of the Wild + Blossoming Tortoise + Spawning Pit + Karn, the Great Creator + Brad Boimler, Eager Ensign

Ashaya, Soul of the Wild

Blossoming Tortoise

Spawning Pit

Karn, the Great Creator

Brad Boimler, Eager Ensign

How it works

1. Animate Spawning Pit using Karn, the Great Creator
2. Activate Spawning Pit's second ability by removing two charge counters from it due to Blossoming Tortoise, creating a 2/2 Spawn artifact creature token.
3. Activate Spawning Pit's first ability by sacrificing the Spawn, putting two charge counters on it.
4. Repeat from step 2.