The Underdark is extremely dangerous, especially to those not native to it. There are the usual dangers associated with caverns: claustrophobia and getting lost. There is no light; most Underdark inhabitants either have highly developed senses other than sight or have developed infravision. Food can be extremely difficult to find, and much of the natural vegetation is poisonous.
In addition to those dangers, the Underdark also is the home of many predators and often-hostile races, including:
