PK Fire is one of the spells Kumatora first starts out with, along with PK Freeze. It's potency has decreased, Only being able to hit 3 enemies. In EarthBound (although that version is called PSI Fire), it can hit many targets as long as it's in a certain row.
PK Fire attacks all enemies currently in the battle. As with most PSI spells, PK Fire has four forms: PK Fire α, PK Fire β, PK Fire γ, and PK Fire Ω. With Omega being the strongest, the spell basically only increases in power and PP cost as the spell's new forms become realized.
PK Fire has a chance to burn the enemy.