Slumm was a type of stimulant that was used to improve athletes' performance. The drug was also highly addictive, and left the user feeling tired after its effects wore off. One method of overcoming the addiction to slumm was to start taking spice, an even more addictive type of drug.
Before Zarandro Vykas became a criminal, he was addicted to slumm.
Sources
- Ultimate Adversaries (First mentioned)