Signs and T-shirts emblazoned with some variation of the letter Q dotted a rally for Donald Trump in Tampa on Tuesday. Paper printouts declaring “We are Q” occupied small sections of the crowd.

One rally-goer named Tyler held out a large coin with Q on it and explained the letter’s sudden prevalence among Trump supporters. “Qanon, the storm, the great awakening,” he told local TV station WPLG.

“What Q stands for is military intelligence, most likely. He’s been talking to all of us. Letting us know the covert battles that are waging between the Deep State and President Trump.”

Tyler, whose last name was not disclosed to WPLG, is one of a growing number of vocal followers of a conspiracy theory, known as Qanon, that has taken hold among some Trump supporters. The theory centers around an anonymous source, Q, who is trying to tell the world about a secret battle being waged by Trump and special counsel Robert Mueller against a pedophile ring filled with celebrities and political elites who have been covertly running the United States government for decades.

“Military intelligence...letting us know what’s going on behind the scenes..”

That’s the headline of #QAnon , a web-based driving force for many Trump supporters that got sudden national notoriety at the Tampa rally....

I asked Tyler to explain. Listen@WPLGLocal10 pic.twitter.com/KMsqQzMxv6 — Glenna Milberg (@GlennaOn10) August 1, 2018

There is no evidence to back the claims. Because, in reality, of course, none of this is true.

That has not stopped the conspiracy theory from gaining an online following. It’s also beginning to show up in the real world at Trump rallies and on billboards. Some people have even acted on the claims.

How did this start?

In December 2016, Edgar M. Welch entered a Washington, D.C., pizza parlor and demanded access to a basement that did not exist. He believed the restaurant was part of a child sex ring, a conspiracy known as Pizzagate. Conspiracy theorists on Reddit and 4chan posted that readers could uncover a child sex ring in the hacked emails of John Podesta — if only one were to replace words like “pizza” with “little girl.”

Eight months later, a person going by “Q” posted for the first time on the anonymous politics message board of 4chan, among the most notorious and extreme places on the internet — and a hotbed of conspiracy talk. Even Q’s first post was riddled with standard conspiracies that never took place.

That marked the start of the Qanon theory, which has drawn on some of the themes that fueled Pizzagate.

The post reads: “HRC [Hillary Rodham Clinton] extradition already in motion effective yesterday with several countries in case of cross border run. Passport approved to be flagged effective 10/30 @ 12:01am. Expect massive riots organized in defiance and others fleeing the US to occur. US M’s will conduct the operation while NG [National Guard] activated. Proof check: Locate a NG member and ask if activated for duty 10/30 across most major cities.”

The second one was even more specific: “Hillary Clinton will be arrested between 7:45 AM - 8:30 AM EST on Monday - the morning on Oct 30, 2017.”

Since then, Q has posted almost 1,800 messages weaving a bizarre theory that now involves a number of anti-Trump movie stars, Democratic politicians, and even companies like the multibillion dollar Mexican cement giant named Cemex.

People lining up for the Trump rally in Tampa today. A lot of the chan anons might treat Q-Anon like a LARP, but by all appearances there are plenty of people who take it seriously irl. pic.twitter.com/uys7kmnAs1 — Travis View (@travis_view) July 31, 2018

Jared Holt, a research associate for Right Wing Watch, which tracks far-right media, has been following the growth of Qanon since its beginning. The sophistication of the conspiracy has not evolved much since then, he said. Followers try to decipher messages from a still-anonymous person who goes by Q, claiming they have top-secret “Q clearance” in the government.

“What the Qanon theory does, as far as political efficacy goes, is it provides Trump’s most fervent supporters a way to explain away any scandal or slip-up the president may face,” Holt said.

Even typos on the president’s Twitter account are viewed as “proofs,” or nods to followers that he is in on the conspiracy.

“All of Trump’s mishaps on the world stage, his detractors in the media, his various scandals can all be effectively be framed within the Qanon lore as attacks that are coordinated against him because he’s ever closer to taking down a global conspiracy committing the most atrocious crimes that could be imagined, like Satanic child sex trafficking, and blood sacrifice,” said Holt.

Many soft deadlines have come and gone for prophecies Q said would come true. Followers believed a tape showing Clinton chopping off the face of a child was set to surface months ago. Clearly, no such tape has come to light.

Still, Q followers find rationales — however unproven and implausible — to explain away the discrepancies. Clinton, they believed, wasn’t extradited, but secretly collared and tagged with an ankle bracelet.

“As far as political impact goes, it solidifies a chunk of the Trump base that will not be swayed by anything that happens in regard to what is reported or what Trump does in public,” Holt said. “It reinforces the idea that Trump is a sort of heroic figure that is going to save America, which was a big line of the campaign.”

Into the mainstream

While the conspiracy theory started in some of the darkest parts of the internet, it has recently shifted to popular social networks and online retailers. Although Amazon.com took “Amazon’s Choice” labels off of Qanon merchandise after NBC News asked the company about it, thousands of Q-related products, like T-shirts, mugs and jewellery, are still available.

QDrops, an app that notifies users about new posts from “Q,” was the No. 10 top paid app on the Apple iTunes store for a day, ranking alongside video games like Minecraft and MLB’s RBI Baseball ‘18. Apple removed QDrops after NBC News contacted the company with questions about the app, but it is still available on Google’s Play store.

Reddit’s Qanon community, r/GreatAwakening, was created to skirt the company’s ban on the Pizzagate subreddit, which was removed two weeks before Welch was arrested in Washington. GreatAwakening now has 50,000 subscribers.

Qanon followers have also proved to be capable of pushing their conspiracy theories into some major platforms. YouTube search results for some celebrities on Monday were taken over by Q fans accusing them of being part of the child sex ring. A search for Tom Hanks returned baseless pedophilia accusations as the top 5 results on Monday, ahead of trailers for his movies. YouTube later deranked the false accusation videos after NBC News asked for comment on them.

Facebook hosts public groups with tens of thousands of followers committed to the theory.

The conspiracy theory has also been referenced by conservative celebrities including Roseanne Barr and Curt Schilling.

Justin Hendrix, executive director at NYC Media Lab, a university consortium focused on media and technology, said he was shocked this week when many of the industry’s leading experts in combatting disinformation hadn’t heard of Qanon.

That changed after Trump’s rally on Tuesday.

“Qanon is easy for casual observers to dismiss,” Hendrix said. “Most of it is so obviously ludicrous. Many that engage with it likely see it as a form of entertainment.”

Many on the web believe gullible users, new to places like 4chan, are being duped by a someone live-action roleplaying, or “larping,” politics in real life. Several recent Q posts have grown defensive about the theory, pointing to media coverage before asking, “all for a LARP?”

While some supporters come off as having a tongue-in-cheek relationship with the theory, Hendrix said it has a definite group of true believers.

“But it's the believers that are dangerous — and there are many," he said. "Unfortunately, media attention will likely only increase its reach.”

Real-world implications

The theory has already caused some followers to take action in the real world.

Billboards in Atlanta and Oklahoma have implored drivers to check out Qanon. Since the beginning of the year, families with young children wearing Qanon shirts have popped up at Trump rallies.

While many followers appear to have embraced the theory with a certain detached irony, it has pushed some people to take extreme action.

QAnon billboards are a thing now. This one's in Georgia. pic.twitter.com/VQ0Hn3T7h6 — Will Sommer (@willsommer) June 29, 2018

An armed Qanon follower blocked traffic at the Hoover Dam last month, demanding the president “Release the OIG report” — Qanon followers believe Trump has secretly been withholding a report from the Office of the Inspector General (OIG) that ties Barack Obama and Clinton to the sex ring. The driver of the van, Matthew P. Wright, has since been sending letters from prison to the president about Qanon.

A Tucson, Arizona, group called Veterans on Patrol overtook a homeless camp over the last several weeks and claimed it had been the site of child sex-trafficking camp. Michael Meyer, who runs the group and is not a veteran, had been livestreaming his accusations on YouTube and Facebook, accruing hundreds of thousands of views from Qanon followers. His page was eventually pulled by Facebook, and he was charged with felony trespassing after a weeks-long standoff with police, who say local officers were doxxed by Qanon followers.

We are trying to identify the man in this picture, which was taken outside my office yesterday (Sun) afternoon. Please contact @NewportBeachPD if you have any details or observed him. We will NOT be intimidated into stopping or changing our course. #Basta pic.twitter.com/YIKS6D0Grq — Michael Avenatti (@MichaelAvenatti) July 30, 2018

Most recently, the Qanon theory turned its attention to Michael Avenatti, the lawyer for Stormy Daniels. “Q” posted Avenatti’s website and pictures of the lawyer’s office building. Less than an hour later, “Q” posted a picture of a man near Avenatti’s office, which the attorney took as a threat.

And “Q” references have been popping up at Trump rallies since the beginning of 2018, with the many “Q” shirts and posters at a recent event putting the theory on the radar of national media.

What worries Holt is what will happen when none of “Q’s” prophecies wind up coming to pass but the zealotry and violent rhetoric of its followers remain.

“The premise that Qanon is operating on is so obviously fictional, but there seems to be at least a chunk of this base that really, truly believes it. That’s what personally worries me. Eventually, I can imagine people growing frustrated that the things that are prophesied don’t come true,” said Holt.

“We have seen this take violent terms, like in the instance of Pizzagate. Unfortunately, it only takes one disturbed person to take it to the next level.”

CORRECTION (Aug. 3, 2018, 3:12 p.m. ET): An earlier version of this article misstated when Reddit banned its "pizzagate" group. Reddit banned the group on Nov. 22, two weeks before the shooting, not in December after the shooting.