While appearing to be nothing more than a magic dart, this missile weapon is of far greater power. 

Once it is hurled, the dart multiplies in the air, even as it speeds toward its tar-get, all the while making an angry buzzing noise similar to the sound of a swarm of hornets. 

When such a dart is hurled, percentile dice are rolled to determine the bonus "to hit" and the appropriate number of darts contained in this particular item. Note that the bonus applies only to hit probability—not to damage, which is of the standard amount (1-3 vs. S or M, 1-2 vs. L) for a dart of normal sort.