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

Prerequisites

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

Steps

1. Activate Amoeboid Changeling by tapping it, giving Ingenious Artillerist 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, as Ingenious Artillerist is a Pirate due to Amoeboid Changeling, creating a Treasure token for each opponent dealt damage this way
5. When the Treasure(s) enter, Ingenious Artillerist triggers 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