Liche Potion

The Liche Potion is a formula which may free the liche Horance from his state of undeath. It appears in  Ultima VII.

Description
This formula was devised by the seer Mordra, who developed it to be used in conjunction with the Soul Cage, that the city of Skara Brae might be freed from Horance's oppressive influence. Comprised of one red cure potion, one black invisibility potion and one potion of Mandrake Essence, it was to have saved the maddened necromancer from the throes of lichedom, restoring him to humanity. Tragically, however, when the mayor, Forsythe, relayed its proportions to the alchemist, Caine he misquoted the amount of mandrake essence by a thousand-fold, and the resulting potion created a massive conflagration which burnt the city to the ground, killing all who lived within it.

When the Avatar came to the desolate island of Skara Brae in the course of their adventures, they would have to re-create this potion that they might at long last restore Horance, and managed to do so with the remnants of Caine's alchemical equipment. Once armed with this formulation and the accompanying cage, the hero was able to return Horance to humanity, ending his despotic reign over the ghosts of the towne.

Trivia

 * In the SNES Port of Ultima VII, Cain was the one who devised the alchemical formula to unmake the liche Rudolfo. In this version of events, the potion never instigated an alchemical explosion, with the citizens of Skara Brae having been presumably slain by Rudolfo himself.