March 11, 2008 -- A 10-year-old Washington state boy died Monday of injuries he suffered Saturday when he buried his head in a sandbox during a play date while mimicking a favorite cartoon character.

A spokeswoman for the Seattle Children's Hospital and Regional Medical Center confirmed that Codey Porter died yesterday afternoon. He had been in critical condition since Saturday, when he stopped breathing in the sand box in a family friend's backyard.

"We are sad to inform you that Codey Porter passed away today at approximately 3:35 p.m," the family said in a statement released by the hospital. "He passed peacefully, with his family at his side. We appreciate all the support and prayers that we have received."

Family members also announced that they would donate Codey's organs so that some other family may benefit.

Codey, a fifth-grader, reportedly was playing among a group of children near his age late Saturday morning when the group came up with an idea inspired by the popular anime-style character "Naruto." According to the official U.S. Naruto Web site, the character is a 13-year-old aspiring ninja who likes to play pranks more than he likes to train.

The mimicry involved Codey's playmates burying him head-first in a one-foot-deep sandbox, Joshua Quantrille told ABC News' Seattle affiliate KOMO-TV. Quantrille, 30, is Codey Porter's half-brother and his three sons were among the boys playing in the sand box Saturday with Codey.

Quantrille said the other children initially thought Codey, buried from his head to the top of his chest, was joking when he started to thrash around. By the time they got help, the boy had already stopped breathing. Adults at the house tried unsuccessfully to administer CPR before emergency medical personnel arrived.

The boy was transported first to Providence Everett Medical Center and was later flown to Seattle, where he remained in critical condition at the children's hospital until his death Monday.

Five children interviewed by investigators told the Swohomish County Sheriff's Office that the burial idea came from the popular cartoon. Sheriff's office detectives, who also spoke with the parents of the children, ruled Codey Porter's death a "tragic accident."

Codey's family has established a memorial fund through the Gold Creek Community Church in Mill Creek, Wash. His principal at Silver Firs Elementary School described the student as a "bright, imaginative boy with many friends."

The Japanese character Naruto was first introduced in 1999 and has since become immensely popular in the United States, expanding a brand that includes a television series, videos, video games, trading cards and toys.

Most of the videos and video games listed on the Naruto Web site are rated T for Teen, but the show has not prompted particular parental backlash about its contents.

Douglas Gentile, director of research at the National Institute on Media and the Family and an assistant psychology professor at Iowa State University, said that no research specific to Naruto has been done, but that the boy's death was a reminder that children -- and everyone else for that matter -- often learn by seeing something and copying it.

"Kids are little sponges, they learn from everything," Gentile said, adding that in the '50s and '60s there was a spike in the number of boys visiting emergency rooms after accidents in which they were acting like Superman. "There isn't something magical about this show."

Gentile drew a distinction between shows, movies and games that are clearly fictional and media featuring realistic criminal behavior. The latter, he said, is much more likely to prompt dangerous behavior. As always, he added, parents should be reminded to talk to their children about the media they are exposed to.

Like Gentile, Nadine Kaslow, chief psychologist at Grady Memorial Hospital in Atlanta and a professor at Emory University's School of Medicine, said there's nothing new about a child imitating a superhero — from Batman and Superman decades ago straight through to today's characters. "It goes back as long as there's been superheroes," she said.

But as children become more closely engaged in the process of play, Kaslow said, they do not think of the consequences their mimicry might have. "They are so focused on their activities, they are not thinking clearly," she said.

With so many children pretending to be superheroes around the world, Codey Porter's story is truly an extreme case, Kaslow said, but one that provides parents another lesson in awareness.

"You don't want to blame the show because millions of kids watch the show and don't take it to this limit," she said. "It's not the show's fault, it's not the kid's fault, it's not the parents' fault.

"That's what an accident is."