The Ooze, Grimgrin, Corpse-Born, March of the Machines, and Master Biomancer

Prerequisites

• The Ooze on the battlefield
• Grimgrin, Corpse-Born on the battlefield
• March of the Machines on the battlefield
• Master Biomancer on the battlefield

Steps

1. Activate Grimgrin by sacrificing a creature with a +1/+1 counter on it
2. When that creature dies, The Ooze triggers, creating a Mutagen artifact token for each +1/+1 counter on the sacrificed creature
3. These artifacts are also 0/0 creatures due to March of the Machines
4. Each Mutagen artifact creature token enters with at least one +1/+1 counter on it due to Master Biomancer
5. Resolve the Grimgrin ability, untapping it and putting a +1/+1 counter on it
6. Repeat from step 1

Results

• Infinite +1/+1 counters on a creature
• Infinite Mutagen tokens
• Infinite artifact ETB
• Infinite artifact LTB
• Infinite artifact sacrifice triggers
• Infinite artifact tokens
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite creature tokens
• Infinite death triggers