To determine a spell's total cost, start with the mana cost (or an alternative cost if another card's effect allows you to pay one instead), add any cost increases (such as kicker), then apply any cost reductions. The spell's mana value remains unchanged, no matter what the total cost to cast it was.

If you put a permanent with a kicker ability onto the battlefield without casting it, you can't kick it.

If you copy a kicked spell on the stack, the copy is also kicked. If the copied spell is a permanent spell, the token the copy of that spell becomes when it enters is also kicked.

If a card or token enters as a copy of a permanent, the new permanent isn't kicked, even if the original was.

If a spell's kicker cost was paid, the spell is "kicked."

The kicker ability doesn't let you pay a kicker cost more than once.

You choose how many targets Fight with Fire has and how the damage is divided as you put the spell onto the stack. Each target must receive at least 1 damage if Fight with Fire is kicked.

If some of the targets are illegal targets as Fight with Fire tries to resolve, the original division of damage still applies and the damage that would have been dealt to the illegal targets is lost.

If Fight with Fire is kicked, it can target creatures, players, and planeswalkers.