It would be interesting to see exactly how intelligent and thought out an AI system could be at destroying us. Would it be barbaric? Would we end up with robots clubbing people and dropping bombs? Would it engineer some type of infectious disease that takes us out? Would it develop a fake shot for immunity, so those people locked away hiding from the disease take the shot, and then all die months later? Does it manipulate us for years by pretending to be millions of different fake users online, and slowly push an agenda that's pro AI and robots, while downvoting everyone against it? Do those people with power, that are against AI start dying of mysterious causes?

Even if it decides to be our friend and to help our species, someone will of course fork that AI and give it a negative personality and goals. Then you have the evil AI trying to hack the friendly AI that exists in our homes, and it's a battle of the robots.

Of course, whether or not AI is even possible, no one knows. If it is, I think we'll achieve it, and we'll open up a remarkable can of worms.