When you cast it, you change the reaction of target NPC 2 steps up or down the Reaction Table. That is the effect. It's the GM who, depending on the reaction and the situation, describes which is the magical effect who caused it. Lets say that the Reaction Table its like:
Now, I can imagine the same wizard in wizard school, memorizing lots of different theorems and tricks to be capable to ensorcell enemies someday, and adapt his spells no matter the situation.