The Incredible Hulk and without summoning sickness).
Easy Prerequisites
An opponent cannot block and kill
The Incredible Hulk.
Mana Needed
({1} magic symbol) ({R} magic symbol) available.
Steps
Activate
Fire Nation Palace's second ability by paying ({1} magic symbol) ({R} magic symbol) and tapping it, giving
The Incredible Hulk firebending 4 until end of turn.
Declare
The Incredible Hulk as an attacker. Its firebending ability triggers, adding ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Holding priority, activate
Walking Ballista's first ability by paying ({4} magic symbol) , putting a +1/+1 counter on it.
Activate
Walking Ballista's second ability by removing a +1/+1 counter from it, dealing 1 damage to
The Incredible Hulk.
The Incredible Hulk triggers, putting a +1/+1 counter on it, untapping it and giving you an additional combat phase after this one.
Repeat from step 2 each combat phase.
Notes
If desired, you can use the remaining ({R} magic symbol) to activate Pyrohemia more times and stack combat phases.