Jennifer S. Altman for The New York Times

The Onion News Network team includes, from left, Will Graham, Marc Lieberman, Carol Kolb and Judy Adler.

For three years The Onion has been spoofing Fox News, CNN and MSNBC with its Onion News Network (theonion.com), perhaps the best parody of cable news anywhere. Short segments are put online every few days, with titles like“Should the Government Stop Dumping Money Into a Giant Hole?” and “Boy’s Tragic Death Could Have Happened to Any Family With 20-Foot Pet Python.”

“About the only funnier cable news is the real stuff,” said Bob Franken, a former Washington correspondent for CNN.

Now the Onion News Network is releasing its equivalent of a feature film, “Future: News From the Year 2137.” In production for about a year, this 12-minute video purports to be a newscast recovered from a ruinous America in which states are named after corporations and citizens are outraged that a doomsday device failed to detonate as planned. “We’re borrowing from Fox News 2137,” Will Graham, the executive producer of the Onion network, said with a chuckle.

The online video will go on sale for $2 at Apple’s iTunes Store on Tuesday, the first time that The Onion has charged for its videos. “We made it so dense that it needs to be watched over again — and maybe slowed down,” said Marc Lieberman, the vice president for business development at The Onion. The future, he said, is “a different lens for our jokes.”

The sale is something of an experiment for The Onion, which has relied solely on advertising to pay for its 300-odd videos to date. If it works, going back in time could be The Onion’s next trick. After all, the network claims to have been founded in 1896.

Even some cable news bosses might concede that their broadcasts are easy to laugh at, with their propensity to overhype every local primary election and willingness to drop everything for a car chase (or, less often, a bear chase). That’s what The Onion exploits, much as “The Daily Show” does on Comedy Central. But on that show Jon Stewart, theWalter Cronkite of fake anchors, uses actual TV clips as the setup for his jokes. The Onion invents its own clips.

Both formats are comedy first, but sometimes double as a potent form of media criticism. “Future: News,” for instance, includes a segment accusing the 2137 media of fear mongering about mutant beetle attacks, a not-so-thinly veiled criticism of the cable coverage of crimes and missing persons. Sounding like a TV news executive, Zesty Lewis (Darbi Worley), the “news giver,” or anchor, in “Future: News,” says, “We report what the public wants to see.”

In an interview at the SoHo offices of The Onion last week, the network’s creators said they tried their best to imitate what they see as cable TV’s slavish pursuit of ratings and advertisers. Mr. Graham said the network’s videos were supposed to resemble CNN and Fox on steroids.

“In a very real way, we look up to them,” he said of cable news makers. “They’re constantly doing things that are more pandering. They’re constantly doing things that are more in your face. Their graphics are getting more swooshy and explosive. We’re always watching them and thinking, ‘How can we top that?’ ”

In an Onion video that was especially popular in TV newsrooms this spring, an anchor and a reporter deconstructed a local news story about a bear running loose in a suburban neighborhood. “Residents were shocked to see this fairly common thing happening,” the anchor intoned as he introduced “an attractive witness” who “described the event in breathless terms.”

The video, whose title can’t be printed here, was “priceless,” the former CNN correspondent Miles O’Brien said. “In all honesty,” he said, “the medium has become a parody of itself. Talk about low-hanging fruit — or shooting fish in a barrel.”

Two former cable news hosts, Bobbie Battista of CNN and Suzanne Sena of Fox News, have freelanced as Onion anchors. (Real news “makes you cry,” Ms. Sena said. “Fake news makes you laugh so hard you cry.”) And the traffic goes both ways: Mr. Graham said one of the Onion network’s graphic designers had been hired away by Fox News.

With a morning show, sports talk show and a C-Span-like channel, perhaps the one thing the Onion News Network lacks is a Glenn Beck or Chris Matthews clone. But it recently added a segment hosted by a semiliterate pundit who wields a rifle.

The Onion is working on two spinoffs for television, a news show for the Independent Film Channel and a sports show for Comedy Central, both expected to make debuts in 2011.

The Onion News Network’s creators say it is critical that the Web videos and the television episodes seem, as the network’s director, Judy Adler, put it, “superauthentic.” (That’s why they are occasionally mistaken for actual newscasts; the Make-a-Wish Foundation still includes a disclaimer on its Web site, wish.org, about a two-year-old video titled “Child Bankrupts Make-a-Wish Foundation With Wish for Unlimited Wishes.”)

To make Onion videos, a staff of about 20 studies newscasts and tries to imitate the distinctive pacing of live television. They also work to keep up with the ever more intense graphics used by cable channels.

The authenticity appeals to television veterans, who say they are avid viewers of The Onion’s videos. Mr. Franken, who worked for CNN between 1986 and 2007 and is now a newspaper columnist for Hearst, said in an e-mail message that the videos accurately capture “the perky anchors, the exceedingly UNperky guests, the overpowering graphics, the underpowering analysis.”

He added, “The serious point these superb humorists make is that we in media are often unintentional self-parodies.”