For more context, my players (3-5 level 6's) are heading to the deepest levels of the Underdark to destroy a powerful object that's:

• Creating flesh-warped monsters.
• Inflicting nearly the entirety of the Underdark with a madness driving them to overpopulated (only affects living and organic species).
• Inducing a very powerful urge to commit extreme aggressive sadism (think cenobites from Hellraiser, Slaanesh from Warhammer, Event Horizon).

They are en route to a dwarven/elvish mountian holy site to gather information and prepare. However, they're going to get ambushed by 2 drider's and might get to the Underdark earlier than unexpected. The drider's are infected with this madness and want to bring the captured to Menzoberranzan so that Lolth will return their natural bodies. My bro does have the Out Of The Abyss adventure book and the others of the group have all the other books.