Smooth Pebble

Smooth Pebble were low level bullets that added more damage than the Crafted Light Shot.

Source
Smooth Pebble was most often dropped by the Cracked Golems and Stone Behemoths at Remtravel's Excavation in Darkshore. Some had also been reported as drops from creatures in Gnomeregan, or from cleaning up the Grime-Encrusted Objects that drop in Gnomeregan.