Out into the Four Seasons Hotel ballroom trotted the movie star horse of the film "The Black Stallion," the one who galloped into the the sunset, swam the wide ocean and dove from a shipwreck's inferno.

Last night, he slipped on the dance floor.

And then relieved himself on the carpet.

But not before flinging a tail over the bare shoulders of Naomi Lawson, a close friend of the Washington International Horse Show dinner dance organizer. She hadn't even begun her first course of terrine of smoked salmon with green peppercorns and basil sauce.

"Just flung it over the back of me," she said, her black spaghetti straps unharmed.

As for the carpet, that was taken care of by a 13-year-old named Aleco Greenberg, who introduced himself as "the poorer-scooper." The son of one of the horse show's board members, he wore a tuxedo and braces.

Here's what an Arabian stallion who runs along shorelines was doing at a dinner dance to honor the opening of Washington's 22nd annual horse show: a

"The Lippizans which we had last year for our attraction just didn't pull the people in," explained True Davis, president of the show. And last year, the week-long show at the Capital Centre finished $40,000 in the red.

So this year, the board members decided the stallion would be a terrific attraction both at the show and the dinner dance beforehand. Leo Cuello, the San Antonio heart surgeon who owns the $1 million horse, thought so too. Especially when Amy Carter got involved.

"He wasn't completely sure at any time," said Hermen Greenberg, who areranged the deal. "But when we found out that he would appear at the White House -- that sold him."

So today at 4 p.m., Amy Carter is scheduled to ride the stallion, named Cass Ole. Kelly Reno, the 14-year-old Colorando rancher's son who starred in the film, will be there, too. "Wellllll, you know, it'd be nice to meet her, but . . ." he said last night at the gala, attired in a white tuxedo with ruffled shirt. In the film he wore raggedy shorts.

But this is the president's daughter, somebody pointed out.

"Yeah, but see, I'm going out with somebody back in Pueblo," he responded.

Reno was standing near the horse's temporary stall outside the ballroom, watching dinner dance patrons attempt to engage Cass Ole in horse talk.

"Come here, you beautiful thing, you," said one woman with cascading red hair. She rubbed his nose, and he, wearing a white collar and black tie, nuzzled appreciatively toward her gown. "Oooops, ooops, oooops," she said.

"Poor horse," said somebody else. "He's had a long day."

"Does the horse like cocktail parties?" inquired another.

"Does the horse like cocktail parties?" responded the woman holding him.

If not, the hundreds of people around him certainly did. Last night's dinner dance was just one in a week of receptions swirling around the horse show itself, budgeted this year to cost $600,000. It opens Sunday. The dance was $125 per person, and profits from it, the show and the other social events go toward charity, like the Girl Scouts and the People-to-People Sports Committee. Only problem is, when there's no profit -- like last year -- the charities don't wind up with much.

"Last year the Girl Scouts got from $6,000 to $10,000 from half their ticket sales," said Davis. And the other charities? "Yeah, we had a few other groups," he said, "but I can't say what they got. It was a minor amount, though."

But if you weren't particularly interested in the balance sheet and Cass Ole last night, there was always jewelry and designer-gown watching. The show is the horse crowd's annual dress-up event, so attendees have to shop with a vengeance and a good many credit cards. Wearing the same thing twice is not only ghastly, it's Neanderthal.

Last night, one woman wore black feathers around her neck that so tickled her chin she may have had trouble consuming her Boston lettuce, watercress and mushroom salad with any delicacy. Another wore two strands of pearls at least two inches past her belly button.

"This is Valentino," said Aliki Bryant, the organizer of the dinner dance who was answering a question about the origin of her black dress with puffy sleeves. "De la Renta was night before last, and last night was Yves St. Laurent. And God, don't ask me what I'm going to wear tommorrow night."

Spotted at the dance were Alejandro Orfila, the secretary-general of the Organization of American States, as well as assorted folks who like the horse scene: Margaret Hodges, Jack and Esther Coopersmith, Juliette McLennan, Evelyn Zlotnick, etc.

They had barely begun buttering their rolls when the horse came out and slipped on the dance floor. His appearance lasted less than 20 seconds. After jumping around nervously, he was quickly led back to his stall.

So all that was left was Aleco, the 13-year-old pooper-scooper.

"Just my luck," he said.

"Get it all, Aleco," said his dad.