The boy now internationally recognized as “Alex From Target” had a very peculiar Monday evening. High school student Alex Christopher LaBeouf, his reported name, emerged from relative obscurity to claim hundreds of thousands of Twitter followers through no act of his own.

A handsome young man, Alex had been working at Target when someone surreptitiously snapped his photograph. The user then beamed the image out to her 14,000 users — with an emphatic “YOOOOOOOOOO” — igniting an utterly bizarre, cautionary tale of Internet fame. From that moment, Alex lost control of events in which he never had any say. His image is now given over to the whims of the Internet, more known for its malevolence than magnanimity.

Alex, who seems befuddled but amused by the turn of events, now has more than 500,000 followers on Twitter. Target tweeted at him. So did Ellen DeGeneres. Alex delighted in the attention, but his apparent acceptance of the situation belied a sobering reality: He never asked for this. As The Washington Post’s Caitlin Dewey put it: “The Internet owns him. He doesn’t own his fans … and he certainly isn’t the agent of his own enormous, newfound fame.”

Such flashes of Internet fame burn hot and fast, and it’s very likely Alex from Target will depart from center stage as quickly as he arrived. But for now, there’s something distinctly voyeuristic, if not exploitative, about his celebrity. He is powerless as hundreds of thousands pass judgement on his appearance.

“Alex from Target is so ugly!!!” one user on Twitter wrote. “HES ACTUALLY UGLY STOP,” added another. “Why does #alexfromtarget look hot in some pics but ugly in others I want answers,” one more Twitter user asked.

Some sleuths tracked down his apparent girlfriend and sent her threatening messages. “Alex from target as a girlfriend damn, we must execute her,” one person wrote on Twitter. Another wrote: “I will find you, and I will kill you.” One more: “B—, no one likes you we want #AlexFromTarget.”

The callousness of such messages reflects the earliest days of spontaneous, random Internet celebrity. An earlier incarnation of Alex from Target was 18-year-old Allison Stokke, now called the “hottest pole vaulter ever.” Her tale of Internet fame, which she did nothing to encourage, began when she was a student at Newport Harbor High School and someone snapped an apparently innocuous image of her at the track.

“At 5 feet 7, Stokke has smooth, olive-colored skin and toned muscles,” The Post’s Eli Saslow wrote in 2007. “In the photo, her vaulting pole rests on her right shoulder. Her right hand appears to be adjusting the elastic band of her ponytail. Her spandex uniform … reveals a bare midriff.” The picture, which a blogger uploaded, went viral at a time when “going viral” was a new phenomenon.

Stokke got 1,000 new messages on MySpace, a video of her posted to YouTube collected hundreds of thousands of views and an impostor created a fake Facebook profile of her. A fan page, www.allisonstokke.com, materialized and rolled out a dozen images of her. On chat forums, “hundreds of anonymous users looked at Stokke’s picture and posted sexual fantasies,” The Post reported.

Stokke felt like a victim. “Even if none of it is illegal, it just all feels really demeaning,” Stokke said. “I worked so hard for pole vaulting and all this other stuff, and it’s almost like that doesn’t matter. Nobody sees that. Nobody really sees me.”

The same thing happened to Caitlin Seida, but for very different reasons. Last year, she logged onto Facebook to discover a new message from a friend. “You’re Internet famous!” the message said. Somehow, an image of her wearing a Halloween outfit from “Lara Croft: Tomb Raider” had splashed across the Internet — but written over the image was “Fridge Raider.”

Seida, who said she’s “larger than someone my height should be,” at first thought it was funny. Then she saw the comments. One told her to “kill herself.” Another: “Heifers like her should be put down.”

“We all know the awful humiliation of a person laughing at you,” she later wrote in an emotional column for Salon. “But that feeling increases tenfold when it seems like everyone is laughing at you. Scrolling through the comments, the world imploded — and took my heart with it.”

It’s tragic, but expected. The harassment of Internet celebrities is a natural progression in their narrative. When Buzzfeed broke the story of Alex from Target, it wrote: “BuzzFeed News reached out to Alex to see if he’s received any harassment after becoming Internet famous in under 12 hours.”

Alex didn’t respond.

Then Alex’s girlfriend was asked the same. “How many threats have you gotten?” one user asked.

Finally, she had enough: “OK, people are going way too far with this.”

But it’s likely they’ll go even farther.