For anyone who has ever lost a cellphone, remember this: it could be worse. You could be the person who left his phone in a bar in California. And it wasn’t just any phone; it was a supersecret version of the next iPhone. That model is not expected to be formally unveiled for a couple of months.

For the people at Apple, it must be like a bad version of the guy walks into a bar joke.

The company is known as the most secretive in Silicon Valley, and leaks are rare. But after the phone prototype was left in a bar in the Silicon Valley town of Redwood City, photos of the device began appearing over the weekend in technology blogs, sparking a frenzy of hype among the Apple-obsessed.

Before long, pictures of the product appeared on Gizmodo, a technology news site, whose editors ripped it apart — as if it were an alien from another planet — to dissect its features. The Web site said late Monday that the phone belonged to an Apple engineer.

The phone’s authenticity was hotly debated, but most bloggers concluded it was real. And a person with knowledge of Apple’s hardware plans who was not authorized to speak on behalf of the company confirmed to The New York Times that it was real.

Apple declined to comment.

“It is very stunning,” said Tim Bajarin, president of Creative Strategies, who has been following Apple for nearly three decades. “Apple has such tight control on new products, and they are kept under wraps diligently and religiously until the day of their release. If it is true, it is really a first.”

Some wondered whether the phone was planted by Apple’s formidable publicity machine.

“For the sake of the person who dropped it, I hope this is a devious marketing scheme,” said Paul Saffo, a veteran Silicon Valley forecaster. “But I think it is unlikely. There is no one else on the planet whose shoes I would less like to be in it at the moment.”

In a blog post on Monday detailing how it obtained the phone, Gizmodo said it was left by an iPhone software engineer at Gourmet Haus Staudt, a German specialty store and beer garden in Redwood City.

The person who found the phone peddled it to Gizmodo, which bought it for $5,000, Nick Denton, chief executive of Gawker Media, which owns Gizmodo, said by instant message.

His company’s sites have had a longstanding practice of paying for scoops, and the windfall was tangible. Traffic spiked on Monday, and at midday more than one million visitors stopped by the site in one hour to see pictures of the coveted gadget.

By late in the day, reports began to surface on the Internet that Apple’s chief executive, Steven P. Jobs, had called Gizmodo to get the device back. Mr. Denton declined to comment, saying any conversation between Mr. Jobs and Gizmodo would most likely have been off the record.

“We haven’t had any formal communication with Apple,” he said. Brian Lam, the editor in chief of Gizmodo, said his publication would “probably” return the device to Apple.

From the front, it looks similar to the current iPhone, but it has sharper edges and is a little thinner. The volume and power buttons are stylistically different, and the back of the phone appears to be a ceramic glass, which would enable better reception. That would address a persistent problem that has plagued the iPhone since its inception three years ago.

Late Monday night, Gizmodo said that it received a letter from Bruce Sewell, Apple’s senior vice president and general counsel, requesting the phone back. “It has come to our attention that Gizmodo is currently in possession of a device that belongs to Apple,” Mr. Sewell wrote in a letter that Gizmodo published.

“This letter constitutes a formal request that you return the device to Apple,” the letter said.