The first halloween costume contest was held in the library three years ago and about 35 people attended. The next year about 50 people came.
Last year the contest moved into the Marina Vista Community Center and more than 350 people showed up, with a line forming outside before the start.
This year the expansion continues, with more than 1,000 people expected to attend the Boulevard Boo in Veterans Park Oct. 27 from noon to 4 p.m.
City of Imperial Beach employee Michelle Posada helped get the city involved last year, said librarian June Engel. She stopped working for the city a few months ago but still played a major role in organizing the event.
"Michelle had the idea to bring us together and create this," Engel said. "And yeah, it got big really fast and I think it's going to be incredible."
The Boys & Girls Club and Navy got involved after that, and this year more than 20 sponsors have helped make Boulevard Boo free.
There will be air jumps, a cake walk, balloon art caricatures, tattoo painter, carnival games, a photo booth, a fortune teller, and yes, a costume contest.
Shamu and a penguin from SeaWorld will be there, and the San Diego Padres Friar may also might come.
The costume contest which ranges from children to adults begins at 1 p.m.
Councilman Ed Spriggs and representatives from the Imperial Beach Fire Department, IB lifeguards and the Sheriff's Department will act as judges.
Top winners in years past include a gnome, a robot, the Queen of Hearts and a Hazmat trooper.
Click here to see a photo gallery of the 2010 costume contest.
Click here to see a photo gallery of the 2011 costume contest.
Food will be for sale from Katy's Cafe, Señor Corn and The InSlider Gourmet Sliders and more.
Public safety and community wellness information booths will also be there.