A Skein of Undoing is a potent curse which utilises "Notura" energy to great effect. Whilst quite costly in this regard, the victim of the Skein will suffer greatly in terms of their memory. Depending on how the spell is cast, the victim may forget the generics of their specialisations - so that a master huntsman will be no better at tracking, woodcraft or marksmanship than anyone else - or the entirety of something they knew - such a scholar no longer knowing a language they once did.