Ashaya, Soul of the Wild + Blossoming Tortoise + Spawning Pit + Tough Cookie + Winding Constrictor

Ashaya, Soul of the Wild

Blossoming Tortoise

Spawning Pit

Tough Cookie

Winding Constrictor

How it works

1. Animate Spawning Pit using Tough Cookie
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.