With the skill of ninjas, they've crept out the sewers and proved their power to mainstream America. First came the comic books. Then came an after-school animated cartoon, followed by 600 products aimed squarely at the booming children's market.
But it wasn't until three weeks ago that their flashing swords, flying kicks and surfer lingo cowabunga-ed them into mainstream awareness.
When the new live-action movie, "Teenage Mutant Ninja Turtles," was released March 30, Donatello, Raphael, Michelangelo and Leonardo, the masked, pizza-loving, three-fingered "heroes in a half shell," brought Turtlemania crashing full force into public view.
"The first weekend we had it we were selling out several shows a day," said Peter Haxton, assistant manager at the Dickinson Theatres, 2339 Iowa.
"We've had a couple of kids who have come in costumes," Haxton said. "Some kids have brought in ninja turtle swords and figures. We had one kid who came in the turtle outfit with the bandana and the little plastic ninja turtle swords."
THE MOVIE, which has grossed $50 million in its first two weekends, is drawing viewers of all ages, he said.
"The kids get really pumped up after they've seen it," he said. "They run around the lobby doing teenage ninja turtle stuff . . . They're running around, calling each other `dude' and saying, `Cowabunga!' They're all pretty enthusiastic."
The enthusiasm is spilling over to local Burger King restaurants, which are offering low-priced video cartoon tapes with a purchase, said Ken Ollila, local franchise owner.
"We're getting an extremely good response," Ollila said "We're selling a lot of videotapes. I think that the Teenage Mutant Ninja Turtle thing is the hottest thing out there right now."
But what, you might ask, is the attraction of mutant turtles?
Ryan Julian, a third-grader at Centennial School, says he has all the ninja turtle toys, except for one, and watches the cartoon show every day after school.
"I LIKE a lot of the guys because they like to party a lot, like Michelangelo. He says a lot of funny things and he does a lot of funny things," Ryan said.
Andrew Schrepf, a first-grader at Pinckney School, said he likes the turtles because "they're like transformed into mutants by this stuff and there's a huge rat that helps them. I liked the movie because it's interesting and neat. It shows a lot of ninja stuff."
Andrew says he like the turtles even better than last year's Batman movie.
"Because Batman is just about one hero and Vicky Vale and the Joker," Andrew said. "This is all four heroes and they go through a lot of places, like the city and the country, where they have different adventures."
The opinions were mixed among some local teachers about whether the green-skinned heroes were weaving their way into the fabric of elementary school life.
WILLIE AMISON, principal at East Heights Elementary school, said he noticed the turtle impact Wednesday when he was going over a reading word list in a first-grade classroom.
"One of the words was turtles and the kids said `I saw that movie,'" Amison said.
Tom Christie, who teaches fifth- and sixth-graders at Deerfield Elementary School, said the movie isn't much of a hit with those students.
Christie said that only six out of 56 students he had asked had seen the movie. And he said most of the students said they didn't plan to see it.
Two Lawrence teachers, mindful of the turtles' popularity, have decided to integrate turtlemania into their lesson plans.
Gini Shoulberg, a first- and second-grade teacher at St. John School, said she originally tried to play it down, but it's a part of her students' lives.
"IT'S A FAD that every industry that can is trying to make a cent off of it," she said. "You see the T-shirts, the pencils, the erasers and the notebook covers; all of that comes in."
Mrs. Shoulberg said she's seen students acting out the ninja turtle fighting scenes from the movie at recess. But she says the fad is mainly captivating the attention of young boys.
"The girls, for the most part are rather yuk about it," she said. "One girl said she was sick and tired of pizza being called turtle food. I asked them about the movie the girls would say it was stupid and the boys would say, `It's awesome.'"
Mrs. Shoulberg also said she's noticed the turtles spilling over into art classes.
"I've noticed the boys making these things with clay. I asked them what they were and they said ninja turtle weapons," she said, laughing.
She said the movie was discussed in class this week and some students thought it was more violent than the animated cartoon show.
"They said they didn't like to see it and some said it gave them bad dreams," she said. "It seems like the cartoons are so much less damaging than the movies."
MRS. SHOULBERG said the age group most interested in the turtles seems to be from preschool through about age 7.
"It's the fantasy," she said. "They're at an age where they just absolutely love the fantasy."
For that reason, she said she made writing assignments this week, using the turtles as a topic.
Barbara Trouslot, who teaches third-graders at Centennial School, also decided to capitalize on turtle interest and channel it into school work.
Her class had a "Ninja Turtle Day" Friday and students were encouraged to bring in their turtle paraphernalia.
"It was very exciting," Mrs. Trouslot said. She used the turtles in lessons on spelling, reading, writing, math and geography.
Students started out looking up what the word mutant meant, what ninja meant and what martial arts were, she said. Then they talked about the origins of the names of the turtles.
Students did creative writing, based on the story line and some read their stories to the class.
They also saw a video of the cartoon so the students could all see the characters and talked about good and evil, she said.
Mrs. Trouslot said the students have used pizza in their math problems. And she handed out little Teenage Mutant Ninja Turtle cookies as a treat.
"Interest is so high, we'll probably use it again in math," she said. "You don't want to do it all the time, but it is exciting."