Malcolm, Keen-Eyed Navigator, Amoeboid Changeling, and Reckless Fireweaver

Prerequisites

• Malcolm, Keen-Eyed Navigator on the battlefield
• Amoeboid Changeling on the battlefield
• Reckless Fireweaver on the battlefield

Steps

1. Activate Amoeboid Changeling by tapping it, giving Reckless Fireweaver all creature types until end of turn
2. Cause an artifact to enter the battlefield under your control
3. Reckless Fireweaver triggers, dealing 1 damage to each opponent
4. Malcolm triggers, as Reckless Fireweaver is a Pirate due to Amoeboid Changeling, creating a Treasure token for each opponent dealt damage this way
5. When the Treasure(s) enter, Reckless Fireweaver triggers that many times
6. Resolve the first Reckless Fireweaver trigger, dealing 1 damage to each opponent
7. Repeat from step 4

Results

• Infinite colored mana
• Infinite damage
• Infinite Treasure tokens