The trailer is a slick piece of work, teasing a mystery (which includes an "invitation" from another civilization) and an expedition featuring co-stars Noomi Rapace and Michael Fassbender, then slowly ratcheting up the tension. Cries of "Get it off! Get if off" suggest a return to the face-hugging alien creatures that have starred in four Alien movies, including Scott's 1979 original. Images in the trailer definitely harken back to that first movie.

Scott, who received scattered standing ovations when he showed up on stage, revealed few details of the plot. He played down the Alien connection, saying that while there has been talk of the movie having "DNA from Alien," once he and Lindelof began story meetings, it morphed into something else.

"It evolved into another universe," he said. "If we're lucky, there'll be a second part. It does leave you with some nice open questions."

Scott talked about how making sci-fi movies has changed since he last tackled the genre. A man in a rubber suit played the alien in Alien, "but today you can pretty much do anything you want" with digital technology, he said. And it's harder to engage audiences these days. "We're almost action-filmed out, almost science fiction-filmed out," Scott said. "So the baseline question is: how original are you going to be?"

Scott didn't really talk about the original aspects of Prometheus, continuing the secrecy around the project that has extended to the actors. "This the closest we'll feel to CIA spies, where we can't tell our loved ones what we are working on," Theron said.

VIDEO: Ridley Scott and Michael Fassbender Explore an 'Alien' Landscape in an International 'Prometheus' Trailer

Unfortunately, the sense of secrecy left the fans gathered in the Convention Center wanting more. In a major departure of convention tradition, the panel didn't take any questions from the audience, instead answering a few questions that were said to have come from Twitter. The move seemed designed to avoid unwanted fan queries.

That development--and the fact that a roughly minute-long IMAX trailer was leaked online in the previous 12 hours, making the trailer Scott introduced not an entirely exclusive reveal for the WonderCon crowd--left some a little disappointed. But, of course, they'll all be in line to see what Scott has come up with on June 8.