Sounds like the "dog" used the Reflect spell. To get rid of it you just need to use Dispell. That gets rid of all stats pluses including Protect, Shell, and, more importantly regarding using your spells against enemies, Reflect.
I hope that works. If you don't have Dispell (i think it's called that, it might be something different i froget, someone else can confirm the name of the spell) then there is an item that has the same effect, but i forget what it is.
Sorry I couldn't be of more help.
Jay