Felldew (Shivering Isles)

A powerful drug found on Elytras, highly addictive with powerful withdrawl effects. Unfortunately, in the quest Addiction, you have to eat Felldew, instantly making you an addict. While felldew is an alchemical ingredient, the only effect listed is the Felldew Effect. It can, however, be turned into a potion when mixed with a Heart of Order, the resulting potion being either one of the Felldew Effect, or one of Jyggalag's Favor.