Some duergar study the use of purple worms in order to excavate the Netherworld at their leisure. While a long shot, this method seems very promising to them. Purple worms could also be of interest to the duergar militarily, if they could be lured toward their enemies. For this, they primarily use thumpers to attract purple worms. By using multiple thumpers working together, it could be possible to direct them on a desired path.