Gilder Bairn, Agatha's Soul Cauldron, and Sanctum Weaver

Prerequisites

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

Steps

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

Results

• Infinite colored mana
• Infinite proliferate