On the planet korriban with the sith corpses that spawn a set of Hssiss the first time you examine them, there is a glitched corpse that infinately spawns Hssiss.The corpse is located in the Sith Temple at the end of the Shryak Caves. After the second "Vision" involving the mined bridge, head east to a path split, then head south until you reach a small room. In the center of the room is the jedi corpse, and each time you examine it 2 Hssiss spawn in the room. If you have a high enough Force Storm and Death Feild, you should be able to harvest 40 Hssiss at a time with no risk to your health (Death Feild x Lots of enemies = Full Health). And since each Hssiss is worth 400xp thats like 16,000xp every 45 seconds.