Gilder Bairn, Biomancer's Familiar, and A Realm Reborn

Prerequisites

• Gilder Bairn on the battlefield
• Biomancer's Familiar on the battlefield
• A Realm Reborn on the battlefield

Steps

1. Activate Gilder Bairn's ability from A Realm Reborn by tapping it, adding
2. Activate Gilder Bairn by paying and untapping it, doubling each counter on target permanent
3. Repeat

Results

• Infinite proliferate for permanents