Karn, the Great Creator, Pemmin's Aura, and Nyx Lotus

Prerequisites

• Karn, the Great Creator on the battlefield
• Pemmin's Aura in hand
• Nyx Lotus on the battlefield
• Nyx Lotus does not have summoning sickness
• You have more than three devotions of blue color
• available

Steps

1. Activate Karn's first loyalty ability, causing Nyx Lotus to become an artifact creature until end of turn
2. Cast Pemmin's Aura by paying , enchanting Nyx Lotus
3. Activate Nyx Lotus by tapping it, adding mana of that color equal to your devotion of that color
4. Activate Pemmin's Aura by paying , untapping Nyx Lotus
5. Repeat from step 2

Results

• Infinite colored mana