Skull of corruption in Oblivion was one of the most badass weapons in the game, it would spawn a clone of the target and they would fight to the death.

In Skyrim it just damages people...

Supposedly it does something with their dreams. I have no idea what that means, and I don't know how to use it, and there's no explanation of it in game.

Thus ... it fails as a feature. In a way. I don't really understand what it does.

Hmm... this thread already got locked once...

That was because it was a "double" by mistake.

I think you are supposed to use it on sleeping NPC's to charge it. I have no idea since I didn't get it. I saved what's-his-name instead. But yeah... the Oblivion versions seems better.

It's a weak artifact. Looks good, but not worth killing Erandur over.
The Oblivion one sounds a lot better.

You fire it at enemies.
And charge it up by pointing it at sleeping people and stealing their dreams. A prompt appears when you put it close to them. You can also charge it up with soul gems.

You just need to steal a lot of dream I suppose, it's supposed to get better.
I don't know I haven't tried it that much yet.

Oblivion Skull was great, but only because of the http://www.uesp.net/wiki/Oblivion:Exploitable_Glitches#Permanently_Clone_Yourself.
Skyrim's needs to be fed first. It damages over a wide area, but harms followers, so not much use if you take them.