Timothy Ferguson's GfF 81 - http://gamesfromfolktales.libsyn.com/081-anosognosia - is all about destroying a skillset.
Question: Using the PeMe guidelines, this seems to imply that a spell can obliterate an Ability or an Art. A series of these could be just devastating. Eliminate the Parma Magica skill, then a target's Techniques, and finally their Hermetic Code (I tend to think all magi have at least a 1 in Code, which may not be so), and you have a husk of a mage not even able to identify their acquired shortcomings, never mind object. A little further, and the target magus may be so addled they don't realize they're a wizard anymore.
This is obviously a gross violation of the Code. A wizard using these spells is likely to find themselves dead in short order, if discovered.
What to do about the affected wizard?