A happy accident keeps on trucking

Forget for the moment the gorgeously rendered Great Barrier Reef, the photo-realistic water and sun effects, the gracefully animated undersea cast, and the painstaking re-creation of Sydney Harbor in “Finding Nemo,” the latest computer-generated feature from Pixar Animation. What hard-core Pixar fans really want to know is: Where’s the Pizza Planet truck?

The battered yellow pickup with a white camper shell and a light-up plastic rocket ship, advertising the fictional Pizza Planet franchise, played a key role in Pixar’s first feature, 1995’s “Toy Story.” Strangely enough, it has become Pixar’s most recurring image, popping up, Hitchcock-like, in every picture the studio has made.

“We have two rules in our movies,” says Andrew Stanton, who wrote and directed “Finding Nemo,” which is being released Friday by Disney. “Get the Pizza Planet truck in there somewhere and always have John Ratzenberger be a voice.” The former gets its most fleeting cameo ever in “Nemo,” whizzing past a dentist’s office where a major part of the film is set, while the latter, whom Stanton calls “our good-luck charm,” gives voice to an entire school of fish.

Calling upon a favorite actor is understandable enough, as are artists inserting animation equivalents of Hirschfeld “Ninas” just for kicks. But how did a rent-a-wreck junk-food wagon wind up as the unifying icon for the studio’s oeuvre?

“It happened by accident for ‘A Bug’s Life,’ ” says Stanton, who co-wrote and co-directed that film. Running short of both time and money to design and create one shot of a human dwelling, under which Bug City would be revealed, the Pixar team hunted through existing images to reuse, settling on a beat-up camper. Needing a vehicle to park beside the camper, they decided to recycle the Pizza Planet truck.

“That started it going and from then on we said, ‘Well, can we put it in again?’ ” Stanton says. That ramshackle camper, incidentally, makes a return appearance along with the truck in 2001’s “Monsters, Inc.” as the bayou dwelling where the villainous Randall gets his comeuppance.

The best showcase for the Pizza Planet truck -- the Pixar folks officially dubbed it a 1978 “Gyoza” -- came in 1998’s “Toy Story 2,” in which Buzz and the toy pack commandeered it to chase greedy toy dealer Al to the airport to rescue Woody. But the Pizza Planet truck is by no means the only bit of in-joking to be found in Pixar films.

* In “Toy Story,” the title of one of the books in Andy’s room is “Tin Toy,” the name of Pixar’s 1988 Oscar-winning short, which screens in front of “Finding Nemo.”

* In “A Bug’s Life,” a circus-themed cookie box bears the banner “J. Grant, Baker,” a tribute to Disney story man Joe Grant and his work on the circus-themed “Dumbo.”

* In “Toy Story 2,” the kids really ran loose through the toy store, filling aisle after aisle of Al’s Toy Barn with such on-the-shelf but off-the-wall products as Impressionist painter action figures.

But such sly, semi-hidden gags are nothing new, as animators have always seemed to possess a special talent for mischief. Cartoons of the 1930s, from all studios, often featured self-referential jokes and caricatures. For 1940’s “Fantasia,” animators patterned the arched-eyebrow glare of the master sorcerer, Yen Sid, on the expressions of Walt Disney (for proof, read “Yen Sid” backward).

A new generation of animation artists loaded in-jokes into such films as 1989’s “The Little Mermaid,” which features Mickey Mouse, Donald Duck and Goofy among King Triton’s underwater minions in one crowd scene, and 1996’s “The Hunchback of Notre Dame,” in which Belle from “Beauty and the Beast,” which is set centuries later, can be glimpsed in a market square.

On occasion an in-joke has backfired, and never more spectacularly than in the case of the 1977 film “The Rescuers,” in which a photo of a nude woman was placed in a background window. Although the image went by too quickly to see in theaters, it freeze-framed quite well, causing Disney to launch a highly publicized recall of more than 3 million video copies of the film in 1999. The real irony is that the image had been discovered years earlier and removed from a previous video release of the film, but Disney went back to the original negative for the 1999 video. (For the record, the alleged hidden salacious images and messages in various Disney animated films that a fundamentalist group protested in the mid-1990s proved to be in the eyes and ears of the beholders.)

Still, past controversies have caused animation producers to be more careful about the images that go into a film. “Everything has to go past legal,” Stanton says, “just to make sure no one’s going to get mad. We’re too big a target.”

For safety’s sake, Pixar commonly uses its own trademarked images. Cowgirl Jessie from “Toy Story 2” made a cameo appearance in “Monsters, Inc.” Similarly, orb-eyed Mike from “Monsters” can be seen snorkeling past the camera in “Finding Nemo.” Buzz Lightyear also shows up in “Nemo,” as do characters from two upcoming Pixar films, 2004’s “The Incredibles” and 2005’s “Cars.” In addition to providing hours of freeze-framed entertainment for today’s DVD generation, this character cross-pollination, says Stanton, is also a sign of a TV kid in the 1960s. “We all remember when the Beverly Hillbillies went on ‘Petticoat Junction,’ or when the Green Hornet was on ‘Batman,’ ” he says. “That rocked our world when we were kids, so we said, ‘Why not?’ ”