Berta, Wise Extrapolator, Cathars' Crusade, and Pentavus

Prerequisites

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

Steps

1. Activate Pentavus by paying and removing a +1/+1 counter from it, creating a creature token
2. When the creature token enters, Cathars' Crusade triggers, putting a +1/+1 counter on each creature you control
3. Berta triggers, adding
4. Repeat

Results

• Infinite +1/+1 counters on most creatures you control
• Infinite ETB
• Infinite creature tokens