Worried about nuclear war?

Just imagine how thousands of harried commuters felt as they ran through Grand Central Station, reached for a copy of the leading afternoon daily to read aboard the 5:18 to New Rochelle, and skimmed the headlines: KABOOM! IT'S WORLD WAR III Michael Jackson, 80 million others dead Reds nuke U.S. after Ron taunts: 'GO AHEAD -- MAKE MY DAY'

Attorney Laura Grossman, briefcase in hand, Nikes on feet, rounded the corner of the Vanderbilt Avenue entrance and snatched a copy of what appeared to be the New York Post from the rack.

"No, that's not a real newspaper," Mohammad Igbal, the newsstand operator, told her. "It's a funny paper."

"I was fooled," Grossman admitted good-naturedly. "I looked at the headline and my eyes popped out -- Michael Jackson Dead! I had to read about it."

What about World War III?

"Oh, they've used that one before."

The real New York Post, the once liberal working-class paper that Australian publisher Rupert Murdoch transformed into a sensationalist tabloid, has carried a few memorable headlines. As well as "World War III," trotted out at least once during the Middle East war, the eye-grabbers have included "Hinckley Is Sane," "Fritz Flip-Flops" and "Headless Body in Topless Bar."

But this is the Post New York Post, a parody put out by Robert Vare and the same crew of satirists that also produced Not The New York Times and Off The Wall Street Journal. It has the same sort of useful service features: "Dr. Joyce Brothers tells you how to beat those nuclear blahs," and advice from socialite/gardening columnist C.Z. Guest on what to do with dead plants. Special photographs of Michael Jackson, taken during his alleged last minutes: "Goodbye, Gloved One." A picture of Mayor Ed Koch dining out: "How'm I chewin'?" And on the front page, an enticing offer: "FIND A FACT INSIDE AND WIN $3 BILLION."

But at $2 an issue instead of the usual 35 cents, the 500,000 press-run spoof has caused some headaches at the newsstands. Bashir Sheikh, the manager of another Grand Central Station newsstand, moved his copies behind the kiosk to avoid confusion. "We had it out for the first hour," he said. "Then things got worse. People were charged $2 for the real Post and 35 cents for the funny paper."

"I fell for it," said Michael Vessio, a Manhattan commuter who grabbed one from a stack sandwiched between The New York Times and The Washington Post in the Pan Am building. "Until I saw that I was dead." "I don't think they need a parody," said his companion, Cynthia Risch. "The Post is already a joke."

In the real New York Post today: "LIZ FINDS A NEW LOVER, and he's Watergate reporter Carl Bernstein"; "ORPHANED POODLES PLAY TOGETHER, WANT TO STAY TOGETHER"; "Claus' von Bulow lawyer attacks step-kids." An article about the California recipient of a baboon's heart carries the head, "BABY FAE BREAKING RECORD!" In the Post New York Post, a platypus rescues a 3-year-old Bronx girl from the clutches of a mugger, only to devour the tot "before her mother's grief-stricken eyes."

The real New York Post's metropolitan editor, Steve Dunleavy, is lampooned more than once. One article under his byline celebrates the fact that the United Nations is out of New York at last, calling it a "miracle on 44th Street." The lead begins, "As the mushroom clouds that covered the city last night began to clear, New Yorkers saw a silver lining . . ."

Dunleavy is not amused. "I find it ambitious in wanting to be funny," he snapped. "I have nothing against a couple of out-of-work journalists making a few bucks . . . A few of them are former Post reporters not noted for their brilliance. . . ."

"I think in the case of plagiarism, if we are going to call it that, I think Mr. Vare has a little experience in that area. I just want to know when I am going to get paid for those bylines. I would never ever write a lead paragraph that long. They made a terrible botch of it."

"Tell Dunleavy that the check is in the mail," said Vare, who, along with fellow humorist Lew Grossberger, worked at the Post pre-Murdoch. "He has never written as well as we made him write. He's just mad because we made up a story better than he or Murdoch have been able to come up with. I mean, they have not been able to kill off 80 million people and Michael Jackson, have they?"