Watch out, dudes! Those lean, mean, green fighting machines are coming out of their shells this Halloween. But don't have a cow, man - Bart Simpson also will be on doorsteps threatening his tricks for treats.

Rentals of Teen-age Mutant Ninja Turtles costumes are among the most popular get-ups this year, a carryover from the characters' box office success, costume-shop owners say."The Ninja Turtles are going like crazy," said Tammy Dooley, warehouse manager for Master's Tuxedo in Charleston. "Everybody just seems to be loving these turtles."

"We've had 57 calls for them in the past week," said Jennifer Rose as she scanned the inventory list at the Costume Co. in the Boston suburb of Arlington. "Kids, adults, male and female.

"We've had so many requests, we're having to turn people down for them. There's a lot of people who ask us if they think people will cancel out. We tell them `not likely.' "

Lookalikes of Fox Television's Simpson family are doing well in some places.

Costumers who want to rent Simpsons outfits are popping up almost as much as Bart's bulging eyes at Stages costume shop in Wheeling, about 30 miles west of Pittsburgh.

"All the Simpsons are doing pretty good," shop spokesman Dan Fincham said.

"The greatest thing about the Simpsons is there's the mom and the dad and the son, so you get a lot of trios like a short guy or a kid and his parents," he said. "The head's the most important part."

But for those who are stuck on being green this Halloween, it's a Ninja or nothing. Theresa Saidy, owner of Adele's of Hollywood in Los Angeles, said Wednesday she's received 20 to 30 calls a day for turtle costumes.

And don't be shellshocked at the price of an outfit. A Ninja costume rental goes for $45 to $90, depending on the quality, Saidy said.

Costumes portraying detective Dick Tracy have had scattered success in the wake of the box office hit. Among women, rock singer Madonna, Depression Era flappers, belly dancers and antebellum outfits are popular.