It’s been 20 years since “The X-Files” opened to viewers’ wanting-to-believe eyes, and the hit paranormal investigation drama’s creator, Chris Carter, doesn’t quite know what to make of that phenomenon.

“It’s surreal,” he told a sold-out crowd Sunday at the Hero Complex Film Festival shortly after entering to a standing ovation. “It’s like an X-File…. Twenty years’ missing time.”

Asked what he might do differently if he made the show now, he said, “It was of its time…. You probably could make the show today, but, I don’t know why, it just feels like it was made exactly when it should have been made.”

The festival’s closing night was devoted to the acclaimed Fox series, and included screenings of three fan-picked episodes – the pilot, which he wrote, “Jose Chung’s From Outer Space” and “Clyde Bruckman’s Final Repose.”

Carter said the pilot scene in which FBI special agent Dana Scully (Gillian Anderson), a skeptical scientist, first meets her new partner, Fox Mulder (David Duchovny), a crusading believer in aliens and conspiracy, wasn’t just their introduction as a duo to the audience, but to him as well: “That’s the first time they really acted together. They didn’t audition together for the parts. We really cast them separately, so we didn’t know there’d be that chemistry. What you were watching was really a kind of test, and it ended up working.”

“Working” might be an understatement: Scully and Mulder’s chemistry quickly became a pop cultural fixation, with rampant will-they-won’t-they speculation.

During the series’ 1993-2002 run, Carter thought they wouldn’t, though he and the writing staff had some fun with fans’ expectations.

“We actually snuck in a lot of kisses, like secretly, like sneaky dream sequences and stuff where they get together. I knew they should never be together. It was wrong.”

His thinking changed, however, when it was time to make the second feature film spun off from the series, 2008’s “The X-Files: I Want to Believe.” In it, viewers saw that Mulder and Scully had finally become a couple. So why bring them together after all those years?

“You couldn’t keep it up any longer,” he explained. “It was ridiculous.”

Carter had a surprise for the fans, bringing out two of the show’s most popular writers, brothers Glen and Darin Morgan, the latter of whom wrote “Jose Chung” and “Clyde Bruckman.”

Glen Morgan, who noted it was his brother’s birthday, recalled being sent the script for “Clyde Bruckman” and, reading the lines for guest star Peter Boyle’s psychic-vision-haunted titular character, realizing, “Oh my God, this is our dad.” Then, clarifying to audience laughter, “He couldn’t predict when people die or anything …”

That episode, for which Boyle and Darin Morgan won Emmys, and “Jose Chung’s From Outer Space” – which Carter called “still such an improbable episode for any TV show” – broadened the series’ stylistic scope by mixing in more humor with the series’ usual science-fiction and horror elements.

“That was the amazing thing to me,” Carter said. “That it could be so many different things.”

Darin Morgan said he appreciated now more than he did then the risks Carter was willing to take on unusual material.

“I’ve had so many situations since ‘The X-Files’ where producers said, ‘I don’t get this,’” the writer said. “People are so unwilling to take a chance on another person. That was so rare. Thanks, Chris.”

There was, of course, one question on every audience member’s mind: Will there be another movie?

“That’s a good question,” Carter said.

Gently prodded to answer, he replied, “The truth is out there.”