Butterflies—not the flying kind but the tummy kind—were everywhere backstage at the Monaco Room of the Beverly Hilton. As her daddy, Laurence Luckinbill, rehearsed his lines as emcee of an annual fashion show benefiting the Los Angeles Children's Museum, and mommy Lucie Arnaz took her seat out front, Katie Luckinbill, 4, prepared to toddle forth as a bridesmaid. "I'm okay," she said. "Look, there's Snoopy!"

The dressing room was a Halloween grab bag of cartoon characters and tiny tots dressed in pricey duds—black leather Chanel-like suits and Christian Lacroix-style party dresses. Richard Dreyfuss, the only parent courageous enough to stay in the dressing room, played stage mom, helping his son, Ben, 3, adjust his bumblebee antennae and giving Jaclyn Smith's son Gaston, 7, a hand tying his tie.

As women dressed in Star Trek outfits seated the 600 museum supporters (each seat went for $65), Luckinbill bragged that he had fathered "60 percent" of the participating celebrity kids—referring to Ben, 14 (Batman), Simon, 8 (Joker), Joe, 6 (a Ghostbuster), and Katie. "We sort of dragged them here, but they thought it would be fun because of the Batman theme and the Star Trek theme. Besides, the museum is worth it" His son Ben was a tad less altruistic. "I get to come out and beat up my little brother," he said. "That's the best part."