Sokka and Suki + Sokka, Swordmaster + Razor Boomerang + Hammer of Purphoros

Sokka and Suki

Sokka, Swordmaster

Razor Boomerang

Hammer of Purphoros

How it works

1. Cast Razor Boomerang by paying 0 due to Sokka, Swordmaster.
2. When Razor Boomerang enters, Sokka and Suki's second ability triggers, creating a 1/1 Ally creature token.
3. When the Ally enters, Sokka and Suki's first ability triggers, attaching Razor Boomerang to the Ally token.
4. Activate the Ally token by tapping it and unattaching Razor Boomerang, dealing 1 damage to any target and returning Razor Boomerang from the battlefield to your hand.
5. Repeat.