Oh man this is funny. I got the screenshot I was hoping it was(nearly):
I managed to fireball an Illusion in a way, that the fireball itself didnt kill the target, but the retaliation triggered the mana shield and that killed the illusion...
But wait, theres more!
The illusion hit me with half its attack points which was EXACTLY the amount of HP, my essence transit gave me back for casting 6 mana... so it looked like it did not retaliate, but it did. Then the weakening occured and everything is fine^^