Swatting, the horrible "prank" that's hit gamers, Justin Bieber, and many more, explained

Imagine you're sitting at home playing some video games. Perhaps you're streaming the game you're playing to some of your friends and fans on YouTube and Twitch.tv. You're having a good time.

Suddenly, your front door crashes open. Men with rifles burst into your living room and tell you to put your arms in the air and stay still, as they aim guns at your face.

But you're not being robbed or attacked by terrorists. You're being swatted.

What is swatting?

Swatting is the act of calling 911 and lying about someone doing something really bad, like holding a hostage, to get dispatchers to send police officers — and particularly a SWAT team — to a victim's location.

The term gets its name from SWAT teams, which are heavily armed, militarized police units used to raid homes, usually for drug searches.

By the Associated Press's count, some celebrities have been victims of the prank, including Tom Cruise, Justin Bieber, and Chris Brown. And historically, it's been used in rare circumstances against friends, peers, and total strangers, all of whom end up the victims of a poorly thought-out attempt at a prank.

But swatting has also become a part of broader internet trolling culture.

As a result, live streamers have become the main victims of swatting. These are people who stream themselves engaging in some sort of activity, typically a video game, to an online audience. Some people do this as a job: They can collect donations or charge for a subscription. And many do it for fun: They want to show off their gaming skills to others.

Because of swatting, though, the fun and games can end with heavily armed police in your living room.

What are some examples of swatting?

Swatting is something that, really, you have to see to believe. So here's one example from 2014, in which someone playing Counter-Strike: Global Offensive gets swatted:

As the Huffington Post reported, the victim in this video, Jordan Mathewson, was in his office, streaming himself playing Counter-Strike, when he began hearing noises in the background. "Uh oh, this isn't good," he said. "They're clearing rooms. What in the world? I think we're getting swatted."

He was right. Pretty soon, a police team came through the door, telling Mathewson, "Don't you fucking move."

The Littleton, Colorado, police department later said in a statement that a caller "claimed to have shot two co-workers, held others hostage, and threatened to shoot them. He stated that if the officers entered he would shoot them as well." So police responded with force.

To some people, this is just a silly prank. But swatting is very dangerous. SWAT teams are heavily armed and prepared to respond swiftly to a dangerous situation. As the local police chief later said, "This is not a game. This is not an online game. We have real guns with real bullets, and there's a potential there for some tragedy." This is a prank that can quite literally get people killed.

Swatting is also a total waste of law enforcement resources, on top of endangering everyone involved. As the FBI explained in 2008, "[T]hese calls are dangerous to first responders and to the victims. The callers often tell tales of hostages about to be executed or bombs about to go off. The community is placed in danger as responders rush to the scene, taking them away from real emergencies. And the officers are placed in danger as unsuspecting residents may try to defend themselves."

Mathewson's story is just one example. There are many others, with some instances captured in compilation videos like this one:

A recent high-profile person to fall victim to swatting was Joshua Holz, the creator of the hilarious "Damn, Daniel" video. According to the local news station ABC7, on February 23 someone called the Riverside, California, police department, claiming to have shot his mother. Police responded and swarmed Holz's home, soon realizing it was a prank call.

But these are just a few examples of swatting. There are many more out there.

Who would do this?

It depends.

Many swatters are just trolls, trying to get a rise out of people on the internet for laughs and personal entertainment. The research shows that internet trolls tend to display personality traits like sadism, psychopathy, and Machiavellianism. So in some cases trolling and swatting are just manifestations of someone's sadism.

For these people, swatting is funny. That's one reason swatting is commonly deployed against the most popular live streamers: Not only does it get the event on camera so people can rewatch it and laugh, but it can also maximize how many people see it if a streamer has tens or hundreds of thousands of viewers (as some do).

Swatting isn't even the only very personal tactic trolls use to disturb and ruin people's lives for personal gain. There's also DDOSing, an easy-to-execute technical attack that floods someone's internet network, causing it to temporarily slow down or shut down. And there's doxxing, in which a troll obtains a person's private information and posts it online for anyone to see and use.

Some swatters also use swatting to blackmail people. Jason Fagone reported in the New York Times Magazine in 2015 on a serial swatter who used the threat of swatting — and other intrusions into people's lives — to coerce girls to be his friend and, among other things, force them to send nude images to him:

Online abuse began to cross over into the physical world. He sent pizzas to their homes. A string of deliverymen climbed the stairs to K.'s apartment in Florida, carrying unappetizing pies: deep-dish pizza with no cheese, pizza with anchovies and jalapeños, double bacon and double pepperoni. He called their cellphones repeatedly and sent "text bombs" of hundreds of messages at a time. If all else failed and Obnoxious couldn't get a hold of a woman, he would start threatening to dispatch a SWAT team to her house, or her parents' house, or her college — a kind of intrusion that couldn't be ignored.

There's another group of swatters who may not be quite as malicious in their intent, even though the effect is very malicious. These people, who are better thought of as justice warriors, may use swatting to get back at someone who did something wrong — like celebrity Chris Brown, who assaulted his partner at the time, Rihanna.

There's a very good chance that these people are just getting really caught up in the internet's outrage machine. As Vox's Brian Resnick explained, many people will show their outrage for someone's actions — both for their personal entertainment and to demonstrate their moral character to others — by joining in internet mobs to punish someone for wrongdoing on Twitter, Facebook, and other social media platforms.

The now-classic example is Justine Sacco, the former communications director with IAC who tweeted, "Going to Africa. Hope I don't get AIDS. Just kidding. I'm white!" The internet went berserk, with thousands of people tweeting at her before IAC fired her, derailing her life and career.

Swatting can be an outgrowth of this kind of behavior. If thousands of people are okay with ruining someone's life or career over one ludicrous tweet, it's not hard to imagine that some of the thousands are willing to take more extreme measures like swatting.

There are many other reasons swatters will cite to try to justify their actions. But trolling and carrying out internet justice are usually the two big reasons.

How do we stop swatting?

Like all crimes, it's impossible to stop all swatting. But there are some precautions that different levels of government, along with internet services, can and do take to help prevent it.

Swatting is already punishable to some extent under the law, but some want to go further. Members of Congress introduced the Anti-Swatting Act in 2015, which would add enhanced penalties for swatting and force a convicted swatter to pay for damages caused by the prank to government agencies and private groups and individuals. Some states, such as California, have also considered or passed laws that explicitly target swatting.

Some swatters have already gone to prison. In 2015, a man in Connecticut got a year in prison for swatting. In another case, a Nebraska man who was part of a swatting ring was sentenced to five years in prison.

Some law enforcement agencies have also taken on the issue by themselves. After an increase in swatting cases, several California police agencies told the AP they're taking more steps to gauge which 911 calls are real and holding back a bit before deploying their full resources, like a SWAT team.

If any good comes out of swatting, it could be these types of changes. There's a lot of evidence that police are way too quick to deploy their militarized units. A Washington Post investigation found, for example, that police in Washington, DC, frequently raid the wrong homes on bad, little, or no evidence, terrorizing innocent people.

Radley Balko, author of Rise of the Warrior Cop, has documented many, many situations in which police use SWAT teams on completely nonviolent offenders, from marijuana growers to poker players. And a report from the American Civil Liberties Union found that 62 percent of analyzed SWAT deployments in 2011 and 2012 were for mere drug searches.

In fact, some have argued that swatters merely take advantage of a system that's way too quick to use force. Fagone explained for the New York Times Magazine:

The Georgia tactical commander, a veteran of the Marines, says that for planned raids, when he and his team are considering whether to deploy, they use a "matrix" of risk factors to decide if a SWAT response is justified: Does the suspect have a history of violence? Does the suspect have weapons? Has the suspect made threats to law enforcement? For a situation in progress, though — an emergency call — there is no time to go through all of that, and from a police point of view, it's better to "respond high and then downgrade" than it is to show up unprepared. So when a situation arises with a possible active shooter, especially one who says he is heavily armed and will kill officers, dispatch sends a text to team members' cellphones to respond to a certain address, and the police are ready for confrontation.

And when the police "respond high," residents can become disoriented. Maybe they assume they are being robbed. Maybe they pick up a gun. In 2011, a former Marine and Iraq war veteran named Jose Guerena was awakened by his wife, who thought she saw intruders outside their home in Arizona. Guerena picked up his AR-15 rifle, with the safety on, to protect his wife and family. SWAT officers entered the house, saw the gun and shot Guerena dozens of times, killing him. They were conducting a drug investigation. In 2010, during a military-­style raid on a home in east Detroit, a police officer looking for a murder suspect accidentally shot and killed a 7-year-old girl while she slept.

Given these stories, it's a fair question: Should one phone call really cause the police to deploy a militarized unit into someone's home?

Part of the problem may be that society just doesn't take it seriously enough. Police agencies may see swatting as a one-off prank, not as part of a pattern of harassment and abuse that can happen on the internet. Internet services may not stop harassment until it spirals out of control — something companies like Twitter have been heavily criticized for. And friends and family may blame the swatting victim, by questioning how he or she got into so much trouble that someone called a SWAT team on them.

But even if all of this changed, stopping swatting is really hard. Sometimes police just can't tell if a call is real, and law enforcement agents need to respond to emergency calls in some fashion. And deterring swatters with tough criminal sanctions might not mean much if people think they can get away with the crime — and they often can by, for example, simply using hard-to-trace internet phone services or prepaid phones.

The ultimate solution, then, may be for people to stop being jerks on the internet. But since that's not likely to happen anytime soon, swatting will continue, putting people's lives at risk, sometimes for no reason other than some laughs.

Watch: Why recording the police is so important

Correction: This article originally misstated the status of anti-swatting legislation in Congress.