Experiment Kraj, Channeler Initiate, and Devoted Druid

Prerequisites

• Experiment Kraj on the battlefield
• Channeler Initiate on the battlefield
• Devoted Druid on the battlefield
• Experiment Kraj does not have summoning sickness
• Channeler Initiate and Devoted Druid have at least one +1/+1 counter on them

Steps

1. Activate Experiment Kraj using Devoted Druid's second ability by putting a -1/-1 counter on Experiment Kraj, untapping Experiment Kraj
2. Activate Experiment Kraj using Channeler Initiate's ability by tapping Experiment Kraj and removing a -1/-1 counter from it, adding one mana of any color
3. Repeat

Results

• Infinite colored mana