Using the SL creation tools, Farmer constructed tiny, almost invisible objects and programmed them to explode into dozens of fragments, flying out at maximum velocity and doing loads of damage. Afterwards the fragments teleport themselves to a random location and start the carnage again. The only way to stop them was for Farmer to shout "STOP!".
As you can guess, chaos ensued when the WMD was unleashed in the town of Jessie. Farmer quickly decided his completely scientific beta testing experiment was a success and went to disarm the grenades. Then he ran into a small problem: he couldn't find the little invisible buggers. With help from Linden labs he managed to remove the bombs, but the legend of the Jesse Massacre lives on.