Gilder Bairn, Agatha's Soul Cauldron, and Gumato

Prerequisites

• Gilder Bairn in exile
• Agatha's Soul Cauldron on the battlefield
• Gumato on the battlefield

Steps

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

Results

• Infinite proliferate