Anyone who has spent time on the internet has come across something that confounds them — a blog post that doesn't seem to make any sense, a rant that goes off the rails, a YouTube video so strange it's hard to tell if the person behind it is sincere or creating performance art.
Often, this content becomes the butt of online jokes, fodder not just for viewers who can't look away but also those who choose to share and mock it.
For some who stumbled upon Nasim Aghdam's prolific library of online videos, that wasn't an uncommon reaction.
Aghdam used YouTube to espouse the benefits of veganism and exercise with videos that were at once surreal and unhinged. In one clip, pulsing electronic music plays in the background while Aghdam stares expressionless at the camera. In another, she dances wearing a sheep mask in front of a picture of a frowning cow before the words "Go Vegan, Go Healthy & Humane" appear across the screen — exactly the kind of fodder that internet users love to point and gawk at.
That was before Aghdam opened fire with a handgun at YouTube's San Bruno, Calif., campus Tuesday, wounding three people before taking her own life.
Those who had seen her clips are now taking stock of their own reactions.
"I feel guilty," Sahar Motallebi wrote on Facebook. "Although I only laughed at her and never shared her posts … we all saw there is an issue with her and we only entertained ourselves or kept quiet about the cyberbullying going on."
Viewers of Aghdam's videos took to social media in the days after her attack, admitting to having made fun of her. In some cases, they appeared to be grappling with remorse. Others seemed to be coming to terms with how what they viewed as an internet joke could have ended so tragically.
"Some of her videos in Farsi had got famous in the Persian community because she acted weird and was talking crazy. People were actually laughing at her stupid videos," one Reddit user wrote.
"Holy crap, I remember that woman. People on the Turkish internet used to make fun of her," wrote another.
Aghdam's videos had made their way back to her native Iran — where social media channels are often blocked — and to Turkey, where a fellow YouTube creator derided her creations in a video of his own. He described one of her videos as "something I can only see in my nightmares."
"If you watch a video of her five times, she'll appear under your bed," the fellow YouTuber says in his September 2016 post.
Such treatment of a random online personality isn't unusual, said Dr. Elias Aboujaoude, a Stanford University psychiatrist and author of "Virtually You: The Dangerous Powers of the E-Personality."
"The negative traits that surface on social media are not new," Aboujaoude said.
In real-life interactions, people generally keep their worst instincts in check. Online, however, people feel less accountable, which often makes it easier to be angry, hostile or even just careless.
"What we see with social media is a shortcut right back to these instincts that have always been there," he said. "But now we have this outlet to bring it to the surface."
Part of what drives the internet's tendency toward mockery is that it normalizes an "it's just a joke" mentality, Aboujaoude said. It's all virtual, it's not real, and if it's not real then it's OK.
"The fact is it has become real," he said. "Society is being transformed in the image of social media. We don't have that excuse anymore. What happens online does not stay there."
Authorities are still trying to determine a motive behind Aghdam's attack. Law enforcement is looking into her frustration with YouTube — a service she used to forge her online identity but later blamed for stifling the reach of her videos, censoring her content and underpaying her for the traffic she attracted.
Her videos have been removed from YouTube and other sites. (YouTube did not respond to a request for comment).
Although trolling and harassment are near constants in online communities — another negative behavior that the web has normalized — they may have an outsized effect on those who turn to the platforms to seek validation, according to psychology experts.
"Social media is so seductive because it's a place where people go to expose themselves in the hope for a positive outcome," said Mary Lamia, a psychologist whose work has focused on the topic of shame. "And when we don't get that positive outcome, it's a recipe for shame."
Some of the responsibility for policing behavior falls on consumers, psychology experts say. They say it's up to individuals to have a conscience, exercise self-control and rein in the habit to point and laugh at whatever weird video is buzzing around social media.
"These companies need to be asking themselves what part they're playing," said Susan Liautaud, an ethics expert at Stanford University. "They're not responsible for everything users do, they're not responsible for what schools or parents should be doing, but they need to be asking themselves about how their products are being misused."