Mighty Mutanimals, Berta, Wise Extrapolator, and Intruder Alarm

Prerequisites

• Mighty Mutanimals on the battlefield
• Berta, Wise Extrapolator on the battlefield
• Intruder Alarm on the battlefield
• available

Steps

1. Activate Berta by paying and tapping it, creating a 0/0 Fractal creature token, and then putting a +1/+1 counter on the Fractal
2. When the Fractal enters, Mighty Mutanimals and Intruder Alarm trigger
3. Resolve the Intruder Alarm trigger, untapping all creatures
4. Resolve the Mighty Mutanimals trigger, putting a +1/+1 counter on Berta
5. Berta triggers, adding
6. Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite creature tokens
• Infinite mana creatures you control can produce
• Infinite untap of creatures