I tend to write villains whose wants or needs parallel that of the hero's. But I want to write an evil villain someday. A so-called Disney villain who is pure evil just for the sake of being evil. Who enjoys their evil acts and revel in them. Cause complex villains are good and all, but a plain evil villain who is like the force of nature itself and who goes "Mwa ha ha ha ha" as they make evil plans or when their plans succeed are just plain COOL!!!
Personally speaking, I think a pure evil villain needs to be done with lots of care.
Like... If it is going to be someone without a reasonable justification of why they're evil, I think you need to really make them feel like a force of nature, as you described.
For example... A villain like Voldemort (from Harry Potter) is terrible, he has no reason to do anything he does aside from being evil because he is evil, it's just dumb and uninteresting. A villain like Cell (from DBZ) is more interesting, because he is basically a psychopath that revels in seeing the terrified faces of people... He is kinda mad and will just do what he thinks is fun for he has no particular goals in mind... And what is fun for him just happens to enjoy wiping humanity out, so he needs to be stopped.
At least that's my take on it, I absolutely hate bad guys that do bad things because they're bad. They need at least some sort of justification... And being mad is a valid justification IMO... Being evil is not though.