Chaos druids are mostly found in the Taverley, Edgeville, and Yanille dungeons. They are commonly used as a training monster due to their high drop rate of grimy herbs. They use a magical attack which has the same animation as Snare and the draining effects of Confuse. Their attack will also stop you from attacking. Chaos Druids are aggressive towards players below combat level 65.
Herb running is a source of income for low-levels. It involves killing Chaos druids for their herbs and banking after a full load. This tactic can make over 100k-200k a trip. If you are keeping all the higher herbs, herb gloves from Fist of Guthixminigame (especially the higher levelled ones, such as Kwuarm gloves) can greatly increase your profits. Even though all the expensive herbs are (uncommon) drops from Chaos Druids, it is notable that Ranarrs tend to drop more frequently than the other expensive herbs.
Bring a fast weapon such as throwing knives (they are weak to ranged, but most by arrows) as there will most likely be multiple players at your location. Ranging is also recommended to ensure that you will attack a chaos druid first over other players. Ice bursting them is one of the few ways to train Magic and earn a profit.
Bring a teleport tab or home teleport to leave quickly for faster banking.
In RuneScape Classic, a PKer could look like a chaos druid by equipping Zamorak Robes and having a beard with white hair. It was the PKer's hope that an inattentive player would attack the PKer, get skulled, and the PKer would kill the victim before he escaped Edgeville Dungeon, or to launch a surprise attack.