What was Dave?

So I was thinking back to season 2, and I started thinking about Dave. It seemed pretty clear to me that Dave wasn't a figment of Hurley's imagination at all, but actually Smokey trying tempt Hurley into killing himself to have one less candidate. But then I looked at the wiki and found that Dave is not listed as one of the forms of the monster. Is it ever explicitly stated what Dave actually was? Could it have actually been a hallucination?