Potion of beneficial mutation
|A potion which gives you a supposedly good mutation.|
Quaffing a potion of beneficial mutation will immediately and near-permanently give you a single mutation from the list of good mutations. This can include a boost to one of your stats, free resistances, and many more things that are (usually) helpful. Be aware that some mutations may restrict your equipment slots, that piles of good mutations may make curing bad mutations much more difficult, and that each mutation you add on will render you slightly more vulnerable to silver ammunition.
Note that ghouls and vampires below satiated cannot mutate and will rot instead, reducing maximum health and possibly taking a temporary hit to stats as well. Vampires don't need to be Alive to be sure that they will avoid these negative effects: Satiated will be enough.