Robert Krulwich may be the only newsman who would attempt to illustrate the brain of a pancake-flipping short-order cook--and do it by creating a huge contraption enveloping two goofy-looking guys in goggles and helmets.

Or hire the rock band They Might Be Giants to compose a song about getting old.

Or hold up a phone to bystanders in Battery Park and ask how many rings it will take until they get annoyed.

All in one show.

"It's fairly high-risk," the ABC correspondent says. "When you do it badly, it's really bad." In fact, he says, Peter Jennings rejects about a third of his ideas for the evening news and "looks at me like I'm from the Planet Zantar."

Compared to the rigid architecture of most television news reports--opening shot, sound bite, video wallpaper, sound bite, closing stand-up--Krulwich's offbeat pieces do have an outer-space quality. One of his new topics, not coincidentally, is whether alien life exists in the universe.

The extraterrestrial search is part of Krulwich's eight weekly "Nightline" specials, starting Thursday at 10 p.m., which also tackle such eclectic issues as the speeding up of daily life, man's brainpower vs. computer intelligence, human cloning, and the possibility of mass extinction. The series, titled "Brave New World," makes ample use of puppets, performance artists, digital artists, "Batman Returns," a comic book, Buster Keaton, a string quartet and a drum-playing robot.

"You don't want to telegraph to people that this is going to be hard or difficult," Krulwich says. "You have to seduce them before they start thinking about it."

Ted Koppel says he's told Krulwich in response to a number of proposals: "That is really a stupid idea, obviously cannot be done on television, and you're the one guy I'm willing to let try it." Likening Krulwich's risk-taking to an ice skater attempting a triple Lutz, the "Nightline" anchor says: "You can look like a real fool if you end up on your butt, but if you make it it's breathtaking. . . . He's a terrific performer."

Adds executive producer Tom Bettag: "He can make you think and laugh at the same time. He's just not like anybody else."

In a cold and cavernous Washington studio the other day, Krulwich is ready for some performance art. There had been a casualty the day before--seven snails from Nebraska had been safely shipped here in ice, but one died during the taping. To Krulwich's right, for another segment, is a small Ferris wheel bearing a dozen nearly identical heads made by a Greenwich Village puppeteer. Behind him looms a giant clock.

Krulwich is sitting on a tall chair next to David Pleasant, a man in dreadlocks who had been his son's African drumming teacher. Pleasant's task is to musically illustrate different rates of speed. When Krulwich says speed is exciting, Pleasant stomps his feet, raps his hands against his body and makes popping sounds with his mouth. Next, when Krulwich talks about controlling speed, Pleasant erupts loudly on a tambourine and harmonica, tap-dancing his way to a different beat.

"There wasn't too much variance there," Krulwich tells him. "I need a high and a low." They try it again.

"Now, can we halve that?" Krulwich asks. "Maybe one hot and one soft is enough."

Pleasant does the third rendition in the sequence. Krulwich stands up, walks toward the camera and intones: "You see, Ted, dabba dabba dabba dabba."

After a polished take, Bettag emerges from the control room to pronounce the segment too long. "Maybe I'm talking too much," Krulwich says. "Is that possible?"

Krulwich, 51, didn't start out as a journalist. He went to Columbia Law School, where he took a writing course taught by Jeff Greenfield, now a CNN anchor. "It was very clear to me from the get-go that this guy should not be a lawyer," Greenfield says. "He had this sparkle with words."

Krulwich belatedly agreed. He quit a New York law firm after two months and became Washington bureau chief for Pacifica radio. He spent six months at Rolling Stone, where his main responsibility, he says, was to persuade gonzo journalist Hunter Thompson to write more. (Thompson would stick the phone in a parrot cage when he called.)

Then it was on to National Public Radio, where Krulwich, among other things, recorded an opera to explain interest rates. He hosted a PBS series on pop culture called "Edge" and joined "CBS This Morning" in 1984.

Krulwich's signature was economics for dummies--deciphering arbitrage by wearing big-nose Groucho glasses, or illustrating the Texaco-Pennzoil battle by holding Ken and Barbie dolls and burying their faces in a wedding cake. And probably no one in the history of television has begun a piece like this: "One way to think about the Social Security problem is to think of yourself as a squirrel."

Equally striking, though, is the way he talks. Which is to say, he talks like some guy yakking at the local Starbucks--naturally, in broken sentences, mixing quick bursts of slang and wit and profundity. ("The pilot can push THIS button right HERE, BEEP BEEP BEEP BEEP BEEP, that means are you sure you wanna DO this, he pushes it AGAIN and that means YEP . . .") In short, he sounds nothing like a serious, deep-voiced anchorman.

"The dirty little secret is I don't know how," Krulwich says, recalling Dan Rather advising him when he hosted a CBS special during the Gulf War. "I felt a little like an impostor. This is a style born of necessity."

Bettag says he'll read a Krulwich script and say, "Robert, this doesn't make any sense on paper"--until the words are married to pictures and visuals. "He second-guesses himself to death. He goes over and over and changes and changes. He can be a real pain in the neck to work with because he's never satisfied."

While colleagues praise Krulwich's intellect, he takes a more sardonic view, admitting that his wife, New York Times reporter Tamar Lewin, "thinks I'm something of a retard." He says he constantly gets preoccupied by such minutiae as a misspelled word. "I'm smart in a way, dumb in another way. I think very anecdotally."

Krulwich once tried to illustrate a segment about a Japanese video game by getting into a car with Connie Chung, racing around and singing songs.

"It was awful," Krulwich says. "It had no point. It was demeaning to me, demeaning to Connie and demeaning to the network."

Since joining ABC in 1994, Krulwich has expanded his horizons to include science and culture, and learned to abbreviate his wisdom for shorter reports on "World News Tonight." During the 1996 Summer Olympics, he designed for a skeptical Jennings a miniature Olympics featuring insects. After track star Michael Johnson set a world record in the 200 meters, Krulwich demonstrated even faster speed by setting up a cockroach race. Reaction was swift--and negative.

"Taking a triumphant black American and comparing him to vermin struck a lot of people as terribly insulting," he concedes.

Prime time was a new experience for Krulwich, who was startled when a top ABC executive introduced him to minute-by-minute ratings. His first piece for the now-defunct "Day One" was on crocodiles, and he held the audience. But his second piece, on a woman running a computer sex-chat line, caused viewers to flee in droves. "Sometimes you think you've just written 'Oklahoma!' and you've actually written something that closes in Philadelphia," he says.

Others have criticized more than his style. James Glassman, then a Washington Post columnist, slammed a 1997 report on the stock market (Krulwich said there were many "yucky" years for investors) for "amateur mistakes" that provided a "distorted picture" of stocks. Krulwich maintains that Glassman's statistical measures of the market were unduly weighted in the opposite direction.

Another Post columnist, David Broder, ripped his 1996 "Frontline" report on campaign donors buying favors, saying Krulwich had been "disingenuous" and that his thesis was "dangerously wrong." That one stung, Krulwich says.

The upcoming "Nightline" series isn't a huge roll of the dice--it's up against the hit show "ER" on Thursday nights--but it's a departure for ABC. "Eight hours is a Dostoevskian amount of television," Krulwich says.

He openly admires the dramatic techniques of "NYPD Blue" and "ER" and the witty style of "The Simpsons." "It's not fair," Krulwich says. "We should be able to play around. . . . We in the news business have been confined to an antique way of storytelling. . . . There's something suppository-like about a lot of television. It goes in, it goes out, you don't seem to notice."

Perhaps that's why the "Brave New World" series features Buck Henry and Jane Curtin trying to clone six Hitlers, dancer Bill T. Jones covered with computer sensors, even a red-gloved boxer bonking Krulwich on the head.

The first episode showcases the narrator's deceptively simple style. He starts out dialing a rotary phone, which seemed perfectly adequate for all those years. Then he dials a push-button phone and saves a few seconds. He goes back to the rotary--and here a slow-motion effect reduces his voice to a guttural crawl: "Now . . . this . . . seems . . . to . . . take . . . forever."

Krulwich's point is that faster technology changes our expectations of how long something should take. "Push-button phones have in a very real way rewired our brains," he explains. Remote controls have made getting up and changing the channel feel like an onerous task. Newfangled phones that respond to spoken commands like "Mom" now make speed-dial seem obsolete. Even the Amish, he reports from Pennsylvania, are using cell phones.

The "Nightline" series has a limited budget by network standards, and an embarrassed Krulwich had to ask the musicians, dancers and performance artists to donate their time for next to nothing. If the series does well, Koppel and company hope the venture will lead to a regular gig for Krulwich.

Despite Krulwich's fancy graphics and soaring images, events sometimes bring him back to earth. After he paid a seamstress to stitch his conception of a one-eyed alien reptile, ABC's green-eyeshade division rejected the $200 expense. "Who's Robert Krulwich?" the accountant asked.