Here's a chilling thought for Halloween: This weekend's festivities will likely unleash countless clones of Jersey Shore stars Nicole "Snooki" Polizzi and Paul "DJ Pauly D" DelVecchio on to America's streets.

That's because Jersey Shore costumes are topping many retailers' lists as the most popular outfit for the Halloween party season, according to The Wall Street Journal (registration required).

This Halloween is the first since the MTV reality show about the antics of a bunch of rowdy Italian-Americans hit the airwaves last December. Costumes based on Snooki's poofy hair and "The Situation's" rippled abs have been flying off store shelves. They have surpassed Lady Gaga to become the top Halloween costume chosen by young adults aged between 18 and 24, according to a poll of 6,000 people conducted by Brand Keys, a New York brand consultant, the Journal reports (other popular holiday costumes this year include characters from James Cameron's blockbuster movie "Avatar," President Barack Obama, Iron Man and Buzz Lightyear).

After a restrained 2009, Americans look set to open their wallets for Halloween this year, with total holiday spending expected to reach nearly $6 billion, according to the National Retail Federation. Indeed, Halloween has become an increasingly lucrative holiday for retailers, with the adult costume market projected to reach almost $1 billion this season, surpassing expectations of $800 million for the children's market, the Journal said.

Seeing the potential of the adult Halloween costume market, MTV Networks launched its first reality-show costume line this year for Jersey Shore, the Journal reports, adding that executives have tried to reproduce characters like Snooki as accurately as possible (there's even a MTV Web page with instructions for how to achieve a total "Snookification" and "out-pouf the pickle queen").

Retailers who are selling out of official Snooki and Pauly D wigs are even offering makeshift Jersey Shore Halloween packages using skin bronzer, furry pink slippers and last year's unsold Amy Winehouse wigs, the Journal said.