Celebrity followers, a shadowy leader and an obsession with cryptic clues to a bizarre mix of international government conspiracies.

This is QAnon: a niche, right-wing cult that has emerged from the recesses of the internet and is now packing out Donald Trump's rallies.

Journalists who knew of the group were alarmed to see the number of placards and T-shirts emblazoned with the letter "Q" visible in the raucous crowd cheering the US President in Tampa, Florida, on Tuesday.

"We are Q," read one sign. "Where we go one we go all," said another.

I am a lifelong Repub...I am changing party this week...the rally and QAnon are
not my GOP...when someone gets killed, this Administration will have blood on its hands

— J. Willson (@jimbowilstone) August 1, 2018

Some of the "Q" signs had a YouTube logo in the centre, after the group on Monday altered the search results on the video-sharing platform so the top hits on a search for Tom Hanks peddled false claims he was a paedophile.

The list of results was interspersed with the hashtags #Qanon and #pizzagate — a reference to the long-running, disturbing conspiracy theory around Hillary Clinton running a child sex ring at a pizza shop.

It is easy to dismiss these ideas as the ravings of a a tiny, unhinged minority, but the delusional beliefs of radical groups including QAnon are motivating people to take dangerous steps.

And with a President who is legitimising extreme and false ideas, the consequences could be devastating.

just some extremely normal people at an extremely normal political rally for an extremely normal president https://t.co/0Gxa9sa81B pic.twitter.com/9Z2pDX9zCg

— Andrew Kirell (@AndrewKirell) July 31, 2018

WATCH: Supporters of President Trump Chant ‘CNN Sucks’ During Jim Acosta’s Live Spot at Florida Rally pic.twitter.com/2fwQQRVsQf

— Breaking911 (@Breaking911) July 31, 2018

What is 'QAnon?'

The group, which is dedicated to fighting the "deep state" under orders from a mysterious leader called "Q", formed from a diverse pool of right-wingers and conspiracy theorists last October after an unexplained comment from the President about "the calm before the storm."

Members are known as "bakers", the Washington Post explains, and make it their mission to decipher clues from Q to "bake" into an understanding of "the storm".

This "storm" reportedly involves elite and powerful groups, particularly the Illuminati, who are trying to control the world and brainwash people.

QAnon members believe Mr Trump created the collusion story as a cover for hiring special counsel Robert Mueller as a heroic "white hat", working to expose Democrats.

What the President calls "Fake News", the group refers to as "Operation Mockingbird," an alleged 1950s CIA program to manipulate the media.

They believe in the theory that the wealthy, Jewish Rothschild family are a satanic cult, and claim Vladimir Putin is one of the few people who can spot satanic influences.

With no evidence, they claim various members of the Democrat party are members of a global child sex trafficking ring.

Their ideas are backed by well-known figures, including disgraced TV star Roseanne Barr, former Boston Red Sox pitcher Curt Schilling and Infowars host Alex Jones, who believes the Sandy Hook shooting was faked.

What are the real-life risks?

When a homeless veterans charity in Tucson, Arizona, stumbled across a shelter in May and decided it had the markings of a child sex ring, QAnon leapt on this as "evidence" of its belief in a Democrat-backed global trafficking operation. It is now calling for photos on the forum 8Chan, linked to the notorious 4Chan.

Police recently began investigating when a man was seen outside Stormy Daniels' lawyer's office after details of where he worked were posted on QAnon threads.

The #pizzagate story resulted in a man opening fire in 2016 on a Washington DC pizza restaurant, which was forced to close.

"Truth warrior" Sarah Ashcraft — the apparent source of the Tom Hanks rumours on Twitter, who describes herself as a "survivor of ritual abuse and mind control" — has almost 50,000 followers. Her profile also features Mr Trump's Make America Great Again slogan.

In a world packed with social media platforms, worrying concepts are now circulated and repeated on alternative networks such as 8Chan and Gab (a right-wing Twitter) as well as mainstream ones including YouTube.

They gain currency, followers and listeners, planting the seed of damaging ideas in people who might never otherwise have heard them.

After news outlets began reporting on QAnon this week, "anons" claimed on their forums it was evidence of a "co-ordinated attack" by the "corrupt" mainstream media — mirroring Mr Trump's aggressive rhetoric on the press.

It is this rhetoric that led to the New York Times holding a closed-door meeting with the President this week, in which it expressed grave concerns over his "deeply troubling" assault on the media.

White House press secretary Sarah Sanders defended the President's attitude towards the media, saying he "fully supports a free press" but the press had a "responsibility" to Americans.

The anons derided the coverage and wrote in posts shared on Twitter: "We are building the TRUTH of our HISTORY so we can expose and dismantle the corruption that has PLAGUED our world for millennia.

"The CHOICE to KNOW what we have found, verified and presented is entirely up to YOU."