How a Magic-User Might Brew A Potion of Lycanthropy

 There are several ways to become a werewolf.

1. Summon and allow yourself to be possessed by a wolf-spirit. Unfortunately, spirits have vendettas, alliances, and uncontrollable passions; one who takes this route to lycanthropy will find himself at the mercy of entity possessing him. Simple (as far as magic goes), but not worth the degradation. 

2. Make a deal with a demon. The Black Hunter Zamiel is known to bestow the power of wolf-walking on those who swear to be his "hounds", but he also likes to hunt babies, virgins, true believers, and other innocents. One may not enjoy such responsibilities.

Actually "Barbatos", by de Plancy, but he fits the idea.

 

3. On the night of a full moon, hunt and kill a wolf, eat its heart, drink its blood, and wear its skin. One must hunt alone, without help from man, magic, or beasts. Any skilled woodsman may accomplish this, but will be incapable of controlling when he transforms and how he acts in the form of a wolf-man, due to the lingering grudge of the slain beast. 

 

5. This method is the safest (relatively speaking- we're talking magic, here, after all) but whereas the other methods may be accomplished by laymen, this operation may only be achieved by a trained magician. 

 

Potion of LycanthropyTaketh thou a wine-bottle of water that hath gathered naturally in the footprints of a wolf. Boil therein slivers of hoary root, called “wolf’s root”, enough so that the decoction seems as milk. Sift the dregs therefrom, and reduce this by an half and part it from the flame. Once it hath ceased to bubble, add thereto a dram of wolf’s spittle, or of blood, collected without slaying the animal. Decant into a silver dish and set it under a glass dome where it may catch the light of the moon, in her fullness, moving it along her arch so that it doth imbibe of her all the night. Repeat this experiment for three nights, preserving the infant liquid in a cold and lightless place, until those nights when the moon is full. After three such nights, the mixture will have grown a skin, like unto cold blood, with the color of shimmering nacre. Return this skin to the vessel and warm over a bath of heated sand until it runneth as water. Pour, by increments, into a phial of aqua vitae, set over a flame and with agitation. When the two are married, plunge the result in very cold water, until the product shows a leaden hue. Once drunk, he who imbibes this elixir shall become a werewolf, assuming this shape whenever it is needful. But beware any who would drink this fell liquor: there is no known antidote for one who thus willingly alters his shape, save death or the Omnipotent Stone of Sages.