Aldir's Power Transfer

This spell is a very taxing but worth while spell for the one the spell is being used on. Once you cast this spell half of your levels get transferred into another being. Casting it is so taxing you take 6d8 damage,become exhausted, and forget how to cast this spell. The effects are permanent boosting people beyond the limits though possible. Say a level 20 wizard cast this spell on a level 20 fighter they now gain half of your wizard levels. They become more powerful but increase power base on what the caster is.