Speak to Lo Shen at 65.3S, 43.4W on the east side of graveyard to begin. Kill 100 Grave Rats. They are only out during the day time. Once you have finished, speak to Lo Shen again for 50 million xp and he lets you use his sack to get bait for Deathtail. You can repeat this kill task after a couple of hours, but the bait can only be done every 3 days. The rats are weak to bludgeon and lightning.