Hellkite Charger + Fire Nation Palace + Roaming Throne

Hellkite Charger

Fire Nation Palace

Roaming Throne

How it works

1. Activate Fire Nation Palace's second ability by paying 1 and tapping it, giving Hellkite Charger firebending 4 until end of turn.
2. Declare Hellkite Charger as an attacker, triggering it and its firebending ability twice.
3. Resolve both Hellkite Charger firebending triggers, adding eight .
4. Resolve the first Hellkite Charger trigger, choosing not to pay.
5. Resolve the second Hellkite Charger trigger, causing you to pay 5 to untap all attacking creatures and to get an additional combat phase after this one.
6. Repeat from step 2.