Rosie Cotton of South Lane, Berta, Wise Extrapolator, and Intruder Alarm

Prerequisites

• Rosie Cotton of South Lane 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. Rosie Cotton and Intruder Alarm trigger
3. Resolve the Intruder Alarm trigger, untapping all creatures
4. Resolve the Rosie Cotton trigger, putting a +1/+1 counter on Berta
5. Berta triggers, adding
6. Repeat

Results

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