Karn, the Great Creator, Pemmin's Aura, and Coveted Jewel

Prerequisites

• Karn, the Great Creator on the battlefield
• Pemmin's Aura in hand
• Coveted Jewel on the battlefield
• Coveted Jewel does not have summoning sickness
• available

Steps

1. Activate Karn's first loyalty ability, causing Coveted Jewel to become an artifact creature until end of turn
2. Cast Pemmin's Aura by paying , enchanting Coveted Jewel
3. Activate Coveted Jewel by tapping it, adding
4. Activate Pemmin's Aura by paying , untapping Coveted Jewel
5. Repeat from step 2

Results

• Infinite colored mana