It showed up out of nowhere, made the most bank in history (for a movie), refused to explain and disappeared for like 15 years, then came back out of nowhere with a sequel movie, a AAA game, and like 3 more movies in the works.
Edit: I think it now has like a Lego line too?
The thing that I think a lot of people forget about the first Avatar is that it was pretty much the first big blockbuster to be available with those RealD 3D glasses. I distinctly remember wanting to go see it so I could check out RealD and find out if it lived up to the hype.
Of course, it had the James Cameron name recognition, so it was probably going to be pretty successful regardless, but I don’t know if it would have been quite so record-shattering if it weren’t for the novelty of RealD, combined with the higher ticket price of 3D showings.