This spell was cast upon a single arrow that was subsequently fired by someone other than the caster. When it was fired, the arrow disappeared and was consumed by the spell's magic. Multiple duplicates of the arrow were created, depending on the experience of the caster. They could not be set aflame, poisoned or otherwise affected by magical enhancements regardless of the state of the original arrow.
Upon the caster's designation, the arrows reappeared in a 90'-long (27.4 m) cone that widened to a 45' (13.7 m) diameter. Rather than merely strike any solid object or creature within the area of effect, the magical arrows darted around for about 12 seconds until they faded away. They could not pass through globes of invulnerability or other powerful magical barriers.
The arrow swarm did not have to take effect immediately, but could be designated to appear at any time, oriented in any direction, at a point 12' (3.7 m) above the ground in any location the caster had traveled to within the previous 24 hours. They could be set to appear under a number of conditions, such as the appearance of a specific individual or those that triggered a magic mouth spell. A casting of dispel magic, limited wish, or wish removed the magic of this spell without triggering its effects.