Ok, I was fighting Grohl in the Nevermind Caves, and then my Witch Doctor (He told me what to do...no, seriously) cast Chain Lightning. When the Lightning hit one of the henchmen it dropped his health low enough to convert him, BUT when it converted the henchman the Chain Lightning proceeded to continue chaining. However, it chained to and damaged MY companions and team. I'm guessing this is a very random thing I came across, I might even be one of the first for it to happen to.