Ashaya, Soul of the Wild + Blossoming Tortoise + Spawning Pit + Mondrak, Glory Dominus + Donatello, Mutant Mechanic

Ashaya, Soul of the Wild

Blossoming Tortoise

Spawning Pit

Mondrak, Glory Dominus

Donatello, Mutant Mechanic

How it works

1. Animate Spawning Pit using Donatello.
2. Activate Spawning Pit's second ability by removing two charge counters from it, creating two creature tokens.
3. Activate Spawning Pit's first ability twice by sacrificing the creature tokens, putting two charge counters on it.
4. Repeat from step 2.