PK Fire
PK Fire (called PSI Fire in the English version of Earthbound) is a special move that can be performed by both Ness and Lucas. It's a projectile attack that fires a bolt that travels in a straight line until it hits an enemy or destructible portion of a stage. If it does not hit either of the aforementioned objects within a few feet, then it disappears. PK Fire differs between the two characters that use it.
Ness
In all games of the Smash series, Ness's PK Fire explodes into a pillar of fire that hits an enemy multiple times, which can lead to potential combos while the enemy is stunned. When Ness fires his PK Fire in midair, the projectile is fired diagonally downwards that creates a falling pillar of fire if the move connects.
Lucas
Lucas's PK Fire always travels horizontally. When the bolt hits an opponent, it hits once, and deals fair knockback to the enemy. Lucas can use his PK Fire to perform a Zapjump and a PK Fire glide.
Origin
In Earthbound, the attack is actually not learned by Ness (something Paula's Trophy in Melee explains). It is described as a wave of fire shot from the fingers and is capable of damaging rows of enemies.
