LOS ANGELES, Oct. 30 - Silly String has been blacklisted in Hollywood.

For this, thanks goes largely to Tom LaBonge, a city councilman who sponsored an ordinance last year making it illegal to "possess, use, sell or distribute Silly String" -- and the assorted knockoffs -- in public areas in Hollywood from 12:01 a.m. on Oct. 31 to noon Nov. 1.

In the second year of the crackdown, red and white "Silly String Prohibited" signs have gone up along Hollywood Boulevard, spelling out the law and warning of a $1,000 fine for violators. Some passers-by have looked at them with confusion.

"I didn't know it was a problem," said Matt Heinlein, a tourist from Zurich.

But many others did. Mr. LaBonge, who sponsored the measure with another councilman, said he took action last year after complaints from city workers about the mess left on the street and from people who did not appreciate pulling Silly String out of their hair. Random sprayings provoked fights, the police said, sometimes with aerosol cans flying.

Only the makers of Silly String know its ingredients, but it is nontoxic and nonflammable. The city ordinance was mainly intended to address the nuisance factor.