Picture: John Locher/AP/African News Agency (ANA)

Las Vegas - The largest thing Matty Roberts had ever organised was a rave in his hometown of Bakersfield, California. It featured a few local bands and a couple of DJs and drew about 350 people.

He was a community college student with plans to transfer to a four-year school and get a degree in engineering. He worked at a vape shop. Fun for him was playing World of Warcraft at his house.

That was 10 months ago - ancient history for the 21-year-old at the centre of the weirdest internet phenomenon of the summer, a plan to organise a mass raid September 20 on Area 51, the top-secret Nevada military base that has long been fodder for conspiracy theories about aliens and UFOs.

The plan - though it could barely be called that - quickly fell apart after Roberts got a visit from the FBI, and the Air Force issued a statement warning people to stay away. It eventually morphed into a far more conventional event, an outdoor concert called Alienstock.

Stagehands spent Wednesday setting up for the September 19 event at the Downtown Las Vegas Events Center as Roberts sat on a white couch and reflected on how tossing a joke into the social media world changed his life.

"I sparked a movement while I was bored at 2 am," he said.

He had been inspired by a post that proposed stealing all of Minnesota's 10,000 lakes. Roberts wanted to try and top it - to marry the perfect blend of absurdity with pop culture.

An idea hit. Quickly, he created a Facebook page that he titled "Storm Area 51: They Can't Stop All of Us."

Then he went to sleep.

When he awoke that morning of June 27, it went just as he thought. He noticed he'd gotten a few dozen likes. Some funny memes were posted. Same with the next day too. He figured it had hit its peak.

Then, on July 1, he was driving to work at the vape shop when his notifications began buzzing on his phone. Over and over to the point he needed to turn them off. His post suddenly had 600 likes. Then 3 000.

People were RSVPing too, saying they believed Roberts had stumbled upon an ingenious idea to uncover rumored secrets of alien autopsies and spaceships stored in hangers on the military base.

One had suggested the storming crowd adopt the forward-leaning running style used by an anime ninja named Naruto Uzumaki to increase speed and outpace security. Roberts doubted Naruto-style would help anybody, least of all him.

"I'm not very fast," he said. "I'm not a very good runner in general."

Eventually the number of RSVPs surpassed a million. "I don't remember the exact date, but I remember it was at 11 p.m. in mid-July. It was a dumpster fire."

The total has since eclipsed 2 million.

Roberts, who soon realised his little joke might not be so funny, decided he'd better go out to the small town of Rachel - population 58 - which is a popular site for Area 51 aficionados who often stay at the town's famous Little A'Le'Inn.

He already knew storming the base was a bad idea and was trying to figure out what to do instead. Looking around, he thought it could be a good place to have a concert under the stars.

So he and a friend came up with Alienstock, initially planning to hold it in Rachel.

They teamed up with Frank DiMaggio, a local promoter in Las Vegas, and got the owners of the inn on board with the plan. Lincoln County issued the necessary permits. But the town was also a little freaked out.

"Law enforcement will be overwhelmed and local residents will step up to protect their property," said a post on the city website. "It will get ugly."

The county commissioners voted to declare a state of emergency if things got out of hand.

Roberts said he was getting concerned about the ability to respond to emergencies. He said that as officials grew uncomfortable with the event, he and DiMaggio decided to take Alienstock to a more appropriate place: Las Vegas.

Cody Theising, manager at the Little A'Le'Inn, said their worries were unfounded. Permits had been approved, parking and camping sites were being sold as needed, and a Las Vegas-based ambulance company had been contracted to provide medical tents and vehicles.

Undeterred, Theising said he has lined up his own musical acts in Rachel for September 19-22. Separately, a UFO convention is being held in Hiko, about 45 minutes away.

Officials are still figuring a crowd will show up in Rachel. It could be 30,000 people, or it could be 10,000. Nobody knows.

Roberts and others believe a few true believers will try to storm Area 51 anyway. Roberts said he has urged people not to, through interviews and social media. "Be prepared to be arrested," he said. Local officials in Rachel are also urging people not to try it.

Theising said Roberts sold out for money.

Roberts and DiMaggio said the owners of the Little A'Le'Inn are capitalising on using the Alienstock name _ even though they don't own the rights to it. Roberts said he is making almost no money on the event.

Roberts said the whole series of events encouraged but also slightly disillusioned him. He said he is now rethinking his college major and may try for a marketing degree. He said he used to be timid about being in front of the camera, but all of the media interviews have forced him to get more comfortable with that.

Roberts also said he has begun to re-evaluate his feelings on the existence of extraterrestrial life. He said he hadn't thought too much about the topic, but in recent months after talking with UFO experts, he's begun to reconsider it.

But he said he's pretty sure of one thing: If anyone tries to actually storm Area 51, they're going to get arrested. The US Air Force, which operates Area 51, has also issued warnings to anyone thinking about trying to get on the base without authorisation.

Even if someone did get past security - beyond doubtful - Roberts doesn't think they'd find aliens or spaceships.

"Just a landing strip, some airplanes and a few buildings," he said. "That's about it."

dpa