I'd like to put this here for discussion, since polymorph is supported via spell mechanics, and a potion with a similar effect cannot be off setting, as we had this story element in some event a while ago.
To prevent abuse for progression of weak characters, the potion should transform the user into a lowest rank creature, e.g. a yulbar or kikiri. I see a lot of potential for dueling fun with characters that would otherwise have very different stats and skills.
Thoughts?