Gilder Bairn, Agatha's Soul Cauldron, and Fanatic of Rhonas

Prerequisites

• Gilder Bairn in exile
• Agatha's Soul Cauldron on the battlefield
• Fanatic of Rhonas on the battlefield

Steps

1. Activate Fanatic of Rhonas by tapping it, adding Activate Fanatic of Rhonas using Gilder Bairn's ability by paying and untapping it, doubling the counters on target permanent
2. Repeat

Results

• Infinite green mana
• Infinite proliferate