Malcolm, Keen-Eyed Navigator, Ingenious Artillerist, and Amoeboid Changeling

Prerequisites

• Malcolm, Keen-Eyed Navigator on the battlefield
• Ingenious Artillerist on the battlefield
• Amoeboid Changeling on the battlefield

Steps

1. Activate Amoeboid Changeling's first ability by tapping it, causing Ingenious Artillerist to gain all creature types until end of turn
2. Cause an artifact to enter the battlefield under your control
3. Ingenious Artillerist triggers, dealing 1 damage to each opponent
4. Malcolm triggers, creating a Treasure token for each opponent dealt damage this way
5. The Treasures enter the battlefield, triggering Ingenious Artillerist that many times
6. Resolve the first Ingenious Artillerist trigger, dealing 1 damage to each opponent
7. Repeat from step 4

Results

• Infinite colored mana
• Infinite damage
• Infinite Treasure tokens