The spell naturally created a flaming fist of roughly the same size as a human first, appearing midair at any location no more than 10 yards (9.1 meters) away. The caster could then direct it anywhere within (55 meters) of themselves, and strike a target with it, whereupon it would explode into a 6-foot-wide (1.8 meters) ball of fire, burning its target. If it collided with a flammable object, then that object could well catch fire. Surprisingly, if the flaming fist missed its target on its first attack, its heat energy was stored and carried over to the next attack. Thus, if it missed once, then hit, it did twice as much damage on the second attack.
Without the caster's intervention, the flaming fist would continue to attack the last target it was given, or if told not to attack, it waited, though this ran the risk of igniting anything nearby. It lasted only a short duration.
In addition to the usual verbal and somatic components, the spell required a glove (made to fit the caster's own hand) with a pinch of phosphorus and a pinch of sulfur placed inside. Glove, phosphorus, and sulfur were all destroyed in the casting.
The spell was developed by the Halruaan mage Daltim Flamefist sometime in the mid-14th century DR. He included it in his spellbook Daltim's Tome of Fire, which he lost in Tethyr in the 1360s DR. It remained a unique spell at the time.