Rex, Cyber-Hound, Pili-Pala, and Whisperer of the Wilds

Prerequisites

• Rex, Cyber-Hound on the battlefield
• Pili-Pala in exile
• Whisperer of the Wilds in exile

Steps

1. Activate Rex using Whisperer of the Wilds's ability by tapping it, adding
2. Activate Rex using Pili-Pala's ability by paying and untapping it, adding one mana of any color
3. Repeat

Results

• Infinite colored mana