|Although this article is based on canonical information, the actual name of this subject is conjectural.|
The fire spell was a simple incantation that conjured flames for whatever purpose it may serve the caster, although in most cases, it was cast to be used offensively. It required the caster to recite 'incendere', which is loosely translated in Latin for 'burning'. Tara performed this spell against the Hellions, and although she was successful in conjuring flames, it had little to no effect on the demons.
By adding words, the spell could be modified to direct the flames, such as when Xander inadverdently set a book on fire by reciting 'librum incendere'.
The fire spell was one of many ways pyrokinesis, or the ability to create and manipulate fire, could be achieved.