Berta, Wise Extrapolator, Intruder Alarm, and Cathars' Crusade

Prerequisites

• Berta, Wise Extrapolator on the battlefield
• Intruder Alarm on the battlefield
• Cathars' Crusade on the battlefield
• available

Steps

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

Results

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