Donatello, the Brains, Mutagen Man, Living Ooze, and Herd Baloth

Prerequisites

• Donatello, the Brains on the battlefield
• Mutagen Man, Living Ooze on the battlefield
• Herd Baloth on the battlefield

Steps

1. Put a +1/+1 counter on Herd Baloth
2. Herd Baloth triggers, creating a creature token and a Mutagen token due to Donatello
3. Activate the Mutagen by paying due to Mutagen Man, tapping and sacrificing it, putting a +1/+1 counter on Herd Baloth
4. Repeat from step 2

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite creature tokens