Rex, Cyber-Hound, Pili-Pala, and Elvish Aberration

Prerequisites

• Rex, Cyber-Hound on the battlefield
• Pili-Pala in exile
• Elvish Aberration in exile
• Rex does not have summoning sickness
• Elvish Aberration and Pili-Pala exiled with a brain counter on them

Steps

1. Activate Rex using Elvish Aberration'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