Fight with Fire

Kicker {5}{R} (You may pay an additional {5}{R} as you cast this spell.)
Fight with Fire deals 5 damage to target creature. If this spell was kicked, it deals 10 damage divided as you choose among any number of targets instead. (Those targets can include players and planeswalkers.)

Pioneer Masters

Dominaria

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

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.

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.