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

Malcolm, Keen-Eyed Navigator

Amoeboid Changeling

Ingenious Artillerist

How it works

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.