"What" is a big riddim, very menacing bassline and a sort of cowbell sound providing the barest bones of a melody. But it sounds like a rip-off of Wiley's "The Morgue" down to the hi-hat pattern. Now, I don't know who did it first but it does sound like a lot of Wiley's eski riddims so I'm inclined to think he did it first. Maybe it was even authorized, who knows.
Wiley's version has a bit more low-end but the biggest difference is the bassline. It is shifted one step in Wonder's version and some envelope is applied to the cutoff. So Wiley's version is more oppressive and this one is more menacing.