Martin Short looks as though his own funniness frightens him. Short is an actor, not a comedian, and so the laughs he gets on "Saturday Night Live" must be shared with the quixotica of characters he has invented: sleazy lawyer Nathan Thurm, codgerly songwriter Irving Cohen, albino lounge lizard Jackie Rogers Jr. and Short's most glorious creation, spindle-topped twitterbug Ed Grimley.

It's virtually official. Ed Grimley is our new national nerd.

"That's funny, I don't think of Ed as a nerd, strangely enough," says Short analytically, sitting in an NBC office that is more of a bare cell, on the 17th floor of the RCA Building in New York. "I just think of him as this little guy. He's his own little event in life."

Short is a big event in life at the moment, but unlike Ed ("Oh! I'm going mental, I must say!"), he is able to contain his enthusiasm. With Billy Crystal, he helped revitalize the ailing "Saturday Night Live" this season and emerged its brightest discovery since Eddie Murphy, though in fact attentive viewers discovered Short long ago, on a Short-lived and uncharacteristically classy ABC sitcom called "The Associates" and, later, for three seasons as a member of the "SCTV Comedy Network" repertory company on NBC and Cinemax.

Grimley is the character that has most endeared Short to audiences, perhaps because in cool and cynical times it's so kookily refreshing to encounter anybody so spasmodically and uncontrollably elatable.

About this wonderful hysterical dance that Ed does, when he's overjoyed about something, like appearing on "Wheel of Fortune" or lending oranges to Tina Turner . . . "The happy dance? I don't know. It's just a stupid dance," Short says. "I don't know, really -- when did I first do the happy dance?" He ponders like an archeologist prowling archives. He can't remember. It just happened, like Einstein stumbling onto E=mc2.

Ed=manic combustion10.

While the actor was widely and wildly acclaimed for his "SNL" contributions this season, it may turn out to have been the short happy dance of Martin Short. He says while he's pleased, if a smidge unnerved, by the high-recognition factor that comes from being featured weekly on "SNL," he's also too experienced at this kind of comedy acting and writing to be thrilled. So he now says he plans not to return to "SNL" next season, at least not on a regular basis.

An NBC spokesman says in fact that none of the series' performers is definitely inked to return and an NBC source indicates that the network isn't even certain "SNL" will be back. A high profit center during its trend-setting Lorne Michaels days, the program was rescued from oblivion by new producer Dick Ebersol but never has achieved the old level of Nielsen nirvana.

NBC Entertainment President Brandon Tartikoff may just decide to kill it and start over, particularly if the few prize packages in the cast scatter.

Harry Shearer, another bright light, walked off the show in midseason, bored with it and displeased with Ebersol. "I can't see Harry and Dick going on any camping trips," says Short, "but I got along great with Dick. Never had any creative problems with him, either." Short and Shearer did the hilarious "Synchronized Swimming" film on the season premiere and the "Lifestyles of the Relatives of the Rich and Famous" film in which Short played Katharine Hepburn's maternal third cousin Nelson, a tremulous hot dog vendor in Central Park.

Short's leaving the show, if he does leave the show, only because "I have a great desire to do something in a longer form than a sketch form" and because the live weekly program was "the greatest pressure cooker I've ever been in." But while he wants to make movies, he also says, "I've been asked to do movies that have ended up making enormous amounts of money that I've declined. It sounds like, 'Aren't I the most wonderful person?' but I really feel dreadful when I'm on either TV or the screen looking like a jerk."

And he isn't kicking himself that he wasn't in films that featured fellow "SCTV" alumni, such as "Strange Brew" (Dave Thomas and Rick Moranis) and "Going Berserk" (John Candy, Joe Flaherty and Eugene Levy). "I would hate to think that in the movie book either of those films became 'The SCTV Movie,' " he says.

Born 34 years ago in Hamilton, Ontario, the youngest of five children, Short remembers himself as having always been somewhat stagestruck, or tubestruck. "I had quiet moments in the attic doing 'The Martin Short Show,' " he says. "It was a television progam on at 8:30 on NBC, maybe alternating with 'The Andy Williams Show.' I used to type things up for TV Guide -- 'Marty's guests are . . . ' I had an applause record. One big section of applause and then I'd come on and sing a song and introduce my guest and put on another record. Then someone would yell 'Dinner' and we'd stop the tape."

He was 15 at the time. "It seemed pretty normal to me." One of his characters goes back even further. "Jackie Rogers was a name in my fantasy world as an 8-year-old. I determined it might be my stage name if I went into show business. 'Martin Short' is not a good name."

Quiet, shy, polite and accommodating, Short does not seem to have a pretentious show business bone in his body, but there is that unmistakable streak of pixilation that identifies the satirist-clown. From the beginning he had to be able to see the dark comic edge to life. Sometimes the edge was just plain dark; Short's father, a steel company vice president, died when Short was 20, and his mother, concertmaster of the Hamilton Philharmonic ("She actually was the first woman concertmaster in North America," he says proudly) died when he was 18.

Short was married in 1980 ("but we've been together since 1970, as they say") and has a baby daughter, Katherine Elizabeth. In his little tennies, with his feet up on the nearly empty desk, Short looks like a kid with wicked tricks up his sleeve. On camera, he often seems coiled to strike. He can curl up into a fetal ball of a character, or he can explode like a water balloon hitting a conventioneer's head. Like his bounteously gifted compatriots from "SCTV," he is particularly good at zinging the studied fatuousness of television personalities.

Although Short does not feel himself part of a particular generation, he is certainly a part of a new baby-boomy show business subculture, one that lampoons and rejects the posturing hauteur and mawkish self-congratulation still blatant in holdovers. The new breed laughs at Jerry Lewis, never with him. As a group, they largely reject the old elitist gospel that show business is a holy calling, that they are of royal blood. Rock stars still cling to that myth, and they make so much noise on stage and off (what with their many "humanitarian" pursuits) that they tend to obscure the real glittering talents of their and our time: Bill Murray, Eddie Murphy, John Candy, David Letterman, Jay Leno, Michael Keaton, Robin Williams, SCTV's Andrea Martin and Catherine O'Hara, and others.

This could be the greatest comedy generation ever.

What is it about Short's creation, Ed Grimley, that is so heartening and compelling? Even Short seems not to know. The character has evolved since Short introduced him at Second City eight years ago during a sketch. Peter Aykroyd, Dan's brother, kept urging Short to make the topknot higher and higher until it got to the Pikes Peak stage where it is now. During a sketch with Robin Duke at Second City, Short says he suddenly made Ed's trademark grimace and the audience screamed. "Well, instinctively I froze. I didn't know why they were laughing but I thought, 'Oh, I'll figure that out later.' And they stared and laughed so then Ed did that. I think it's like other characters that I do, a facet of my personality."

So now, are kids running around saying "It's very decent, I must say" and "Give me a break" to each other? "Oh, they're going farther than that," Short says. On Short's wall, near a little gaggle of index cards on which sketch ideas have been written ("most of these will never see the light of day") is a photo sent in by a 7-year-old from Littleton, Colo. The boy is dressed up like Ed Grimley, his pants pulled up almost to his Adam's apple, his hair twirled and lacquered into this great screw. "Yes. It's frightening to think that America is doing this," Short says, brandishing a whole sheaf of photos sent in by the kid. "I get pictures from girls who have done it."

Short had the chance to appear on "Saturday Night Live" during its first phase; Lorne Michaels invited him into the repertory players in 1979. But Short opted instead for the role of Tucker Kerwin, boyish law office intern, in the highly promising new comedy series "The Associates." James L. Brooks, of "Mary Tyler Moore" and "Terms of Endearment" fame, was one of its creators. It had everything going for it, including critical raves, but it was on the wrong network, ABC, which canceled it quickly.

Wilfrid Hyde-White, the veteran British character actor (Pickering in "My Fair Lady"), played Emerson Marshall, the senior partner and was notorious around the set for a refusal to take the scripts too literally, or to memorize them too thoroughly. Reminded of this, Short launches immediately into Hyde-White's venerable growl. " 'My darling boy, oh my angel, have you eaten?' That's what he'd always be most curious about," Short recalls. "'Hello, my darling boy, have you eaten? Oh my angel, my darling, where are the producers? Are they around?'

"I don't know if he forgot lines or just chose not to learn them to begin with. As Wilfrid often said about lines, he learned the good ones and forgot the bad ones. I remember one scene where a lawyer, played by Joe Regalbuto, asked him to a party and there was a whole page of dialogue that was tantamount to: 'I remember when I went to such-and-such party at the home of the great Cole Porter and Lena Horne sang and she said to me, "Nice bones," and I also remember being at another party with the great Babe Ruth who said to me, "Emerson, tomorrow I will tell people I will hit a home run for a little boy, but I'll actually be hitting it for you." Can you compare your party to that?'

"And Joe says no. And Wilfrid says, 'Will you have lots of gin?' 'Yes.' 'I'll be there.'

"It was just soooo well written. And Wilfrid said it word for word. But if he wasn't crazy about the scene, and he had to come into your office or my apartment or wherever, he would go, 'Hello my darling, oh, what is this new maga-zeeen?' and pick it up off the table, and that meant the script pages were hidden in it."

Although he takes enormous pains not to compare "SCTV," which followed "The Associates," with "Saturday Night Live," Short does describe working on SCTV as a rather magnificent experience, withholding such raves for "SNL." He says, "The thing about SCTV is that it's one of those few situations that have occurred where the cast did have an enormous amount of control over the show." The lunatics ran a heavenly asylum, currently available to area viewers in reruns on Channel 22, one of the Maryland Public Television stations, weeknights at 11.

As a late arrival to the group, Short was particularly apprehensive about whether the material he wrote and performed was working (there was no live audience because of the taping schedule). "My reputation was that I would ask the cleaning staff what they thought," Short says. He's not bitter about NBC for canceling the program, he says, because after all, "ABC and CBS never would have even put us on."

Although the material generally dragged on "SNL" this season, it was a good year for Short. He particularly liked the show on which the Rev. Jesse Jackson was guest host. Jackson did a sketch with Short as Ed Grimley, a funny "Twilight Zone" thing set on an airplane. "He'd go, 'Ohhhh, who is this guy?' " Short says. " 'Dr. Grimley,' he kept calling me. 'Dr. Grimley.' He was fun. He was fun. He had a good time here, I think."

On the last show, the multimedia event known as Howard Cosell was guest host, reunited with performers like Christopher Guest and Billy Crystal who appeared with Cosell on his own variety series, ironically or not called "Saturday Night Live with Howard Cosell," on ABC in the mid-'70s.

"Howard was great," says Short. "He just kind of looked at me and said, 'Meshuggeneh.' He's quite the personality. It's so great to know precisely how somebody feels about everything. He was 100 percent committed to the show. He had tremendous energy."

Negotiations with NBC about next season will continue. Short will be in Boston on May 4 to emcee the New England Emmy Awards telecast there. He plans a vacation in Jamaica. And he keeps reading movie scripts hoping for something that will appeal to him.

"I'd love to a Broadway musical," he says, frankly gaga at the prospect. "That's my dream. I'd love to do a great wonderful original thing where I could be funny and perform. I love theater." He's looking almost like Judy Garland contemplating rainbows. For all the experience and the raves and the artfully earned laughs, Martin Short is back in the attic now and "The Martin Short Show" is just about to go on the air. But this time, no one is likely to holler "Dinner" and break it up.