When trying to understand what has befallen Comet Ping Pong, a pizza restaurant in Washington, D.C., over the past few weeks, should one start with the gun or with the lies? Both are durable; both are dangerous. The gun is an AR-15-style assault rifle that a man, reportedly a twenty-eight-year-old named Edgar Maddison Welch, carried into the restaurant on Sunday. According to press accounts, Welch waved the gun, pointed it at an employee, and then fired, thankfully not hitting anyone. Customers ran out; nearby businesses, including a bookstore, went into lockdown. The police managed to arrest Welch. He had another gun in his car, and he had a motive. He told the police that he had come to “self-investigate” a conspiracy theory, or set of theories, known as Pizzagate. These theories, which, most broadly put, place Hillary Clinton at the center of an international child-sex-trafficking ring, are the lies, and they are almost incomprehensible. The mystery within the mystery is how anybody with a shred of good will would even try to connect point A to point B. Foremost among those nonetheless doing so are Donald Trump-supporting social-media figures, including the son of retired General Michael Flynn, the President-elect’s choice for national-security adviser. (General Flynn himself hasn’t tweeted Pizzagate allegations, but he has tweeted stories about different pedophilia-related conspiracy theories, also supposedly entangling Clinton.)

The charge at the center of Pizzagate is this: Comet Ping Pong is where high-ranking Democrats go when they want pizza. But “pizza” is not pizza. It is a code word for sexually exploitable young girls, or maybe for young boys, or for infants trafficked from Haiti and killed for their organs, which are then trafficked further. And John Podesta talked about pizza in his e-mails, which were released by Wikileaks. He talked about pizza more than once. Again, it’s hard to know where to start—by asking what the proof is or by asking why anyone would ever posit these notions as something that needed proving or disproving. Often, conspiracy theories are grafted onto something that seems like a mystery, even if it’s not, such as the suicide of Vince Foster, who had worked with Hillary Clinton in Arkansas and joined her husband’s Administration. That human tragedy was exploited by the Clintons’ political opponents and spun into strange stories involving murder. Pizzagate lacks even that nub. There is nothing to explain—no missing children, no accusers, no break-ins involving intelligence agents, no odd incidents, no inexplicable phone calls from powerful people, no baseless firing of someone asking questions, no hit-and-run death of someone who knew too much. But if you find it odd that any given person in America would, now and again, want to eat pizza; if you think that it is suspicious that people getting together to watch something on TV would do so at a pizza place; if you think that the phrase “I could bring a pizza home” is so bizarre that it must mean something else; or if hearing that something is baked in “a pizza oven” causes you to envision Hansel-and-Gretel-like images of child murder with the possible involvement of international terrorists and money launderers (and that is one of the charges), then this is the conspiracy theory for you.

Here is why Pizzagaters say that all this matters, though it’s not clear why any of it would: Comet Ping Pong is owned by a man named James Alefantis. He was once involved with David Brock, a former right-wing journalist who became a Hillary Clinton supporter and worked to get her elected. Alefantis has e-mailed with Podesta, including once to tell him about an Obama fund-raiser taking place at the restaurant, and to ask if he might want to stop by and maybe have dinner. Comet Ping Pong has a haute-hipsterish decor, and a certain number of its clients are journalists or work in politics. It has Ping-Pong tables and displays an image of two Ping-Pong paddles on its menu; if you squint, they look like a butterfly, and a butterfly may or may not be an international symbol beckoning people who sexually abuse children. There may be a subterranean network of rooms and tunnels beneath the restaurant that are used for imprisonment, trafficking, and other unspeakable things. (Alefantis told the BBC, “We don’t even have a basement.”) There is also an e-mail thread in which it is strongly suggested that Podesta may have once had a map that showed where to find pizza on Martha’s Vineyard. (So not only in Washington!) The authorities are, allegedly, covering it all up. These suppositions have been embroidered on and combined with other fabrications in long threads on Reddit, 4Chan, and elsewhere. (BuzzFeed has mapped out how the theory spread.) There is no real search for “truth,” only what amounts to conspiracy fan-fiction. The only actual threat to children seems to have come from Pizzagaters who, according to press reports, have collected pictures of children on the Instagram and Facebook pages of people who “liked” Comet Ping Pong’s pages, then republished them as identifying putative victims. The threats to families—to Alefantis and his staff, and to people in businesses nearby (who have been accused of, among other things, being linked to the ring via the tunnel network)—have become frequent and, as the events of this weekend indicate, have moved beyond the realm of fantasy.

On Sunday night, after the man with the gun walked into the restaurant, General Flynn’s son tweeted, “Until #Pizzagate proven to be false, it’ll remain a story. The left seems to forget #PodestaEmails and the many ‘coincidence’ tied to it.” But this makes about as much sense as demanding that Comet Ping Pong prove that it is not the secret base of space aliens who are plotting to take over the world through their agents in the Democratic Party. Indeed, by some measures it makes less sense. (“Comet Ping Pong” is at least a plausible code name for interstellar travel. And do you know who talks unironically about U.F.O.s? John Podesta.)

Pizzagate seems to have really taken hold during the Presidential campaign, in the period after the release of an “Access Hollywood” video that showed Trump bragging about grabbing the genitals of women he had just met. He dismissed the comments by calling them “locker-room talk,” and by bringing up allegations of sexual misconduct against Bill Clinton. Trump’s supporters went further, attempting to turn both Clintons into sex-crime monsters. The Washington City Paper, in a look at Pizzagate a few days before the election, offered the view that, when Podesta’s e-mails were publicized, some Trump supporters hoped that they would provide the ingredients to substantiate such a scandal. But all they found was pizza, and pizza would have to do.

Which is more alarming: the idea that Pizzagate is being promoted by politically motivated cynics who don’t actually believe it, or that people with influence and proximity to power, including people with access to the President-elect, are really susceptible to this sort of nonsense? Both can be the case; fabricators and wide-eyed believers can be side by side, in Twitter feeds or Trump Tower, or, soon, in the White House. Many things are likely to go wrong for Trump and to disappoint his supporters. The fear is that he and they will try to explain his failings by pushing conspiracy theories of all kinds. The spirit of Pizzagate could become as commonplace, in this country, as the smell of pizza. And how does one even measure power and influence in the context of social media, or, for that matter, in a country with few effective gun-control laws and a President-elect who got crowds cheering with talk of armed citizens taking down terrorists in crowded cafés? How much power belongs to a man in his twenties walking into a pizza place with an assault rifle, looking for secret chambers and hidden messages?