Juiblex

Juiblex is one of the demon lords that have their own lair in Gehennom. He can engulf and make ill any character he meets and will spit acid venom.

Like other demon lords, Juiblex can and will teleport to meet you. Dealing with him is quite simple, you only need a unicorn horn, a wand of digging, and a weapon of some kind. When he engulfs you, zap him with the wand, then hit him once and he will die. This is because zapping a wand of digging from inside a monster causes severe damage to that monster and their hit points is reduced to 1. Juiblex is also vulnerable to stoning.