-By Elena Malykhina and Steve Miller

Bold, risqué and quirky sums up a new viral marketing push for Levi's dubbed "Unbutton Your Beast." Already raising eyebrows, the online effort allows consumers to get creative with a pair of 501 jeans that unzip to reveal a talking creature.

Starting today, consumers can visit Unbuttonyourbeast.com where they will be greeted by a large pair of jeans that asks them to create, customize and send their own "beast." Site visitors can choose from such creatures as "Paul the Pincher," "Sock Nasty," "Honky Tonk Hank" and "Saucy Sal," then add a pre-recorded message or record their own via phone technology that captures voices.

The concept is based on the success of San Francisco agency EVB’s work over the past two holiday seasons with an online viral campaign for Office Max called “Elf Yourself,” which allowed Web surfers to morph into dancing pixies and share the characters with others. EVB did something similar for Kodak last month with "Make Me Super," where consumers could add their visages to a video showing them wearing superhero costumes. "Unbutton Your Beast," also via EVB is also meant to encourage consumers to unleash their inner creativity and, in this case, literally "unbutton themselves," said Lauren Harwell, EVB's creative director.

"Unbutton Your Beast" is part of a global brand campaign for Levi's dubbed "Live Unbuttoned" for 501 jeans, which launched in July. That campaign was followed by another one in August called "Unbuttoned," also via EVB, and featured a dozen up-and-coming celebrities in print and online ads. The point of the ads was to show real people behind stars like up-and-coming singer Estelle.

The target audience for "Live Unbuttoned" is 18- to 24-year-old males, who are not familiar with straight leg jeans since they grew up wearing "loose and baggy" jeans, said Robert Cameron vp-marketing at Levi. "It's aimed at that age group of guy, so it's that kind of humor," Cameron said, referring to the "beast" effort. "The whole purpose is that we want kids to know that the key feature of the 501 jean is the button fly. When you 'unbutton your beast,' you can play this game and have a greeting card to send to a friend."

Not everyone gets the joke. Since the site's launch today, bloggers have been posting reactions that call the marketing push "tasteless" and "indecent." Some have gone as far as suggesting that EVB and Levi put a PG-13 rating on the site to caution parents.

Dan Isett, director of public policy for the Parents Television Council, Los Angeles, called Cameron's assertion that the site was aimed at 18- to 24-year-old males "the height of hypocrisy."

"Levi's has been determined to do is the push the envelope in terms of its marketing," Isett said. "I think you would be hard pressed to find a parent who would see this site . . . and consider [it] appropriate."

Cameron assured, however, that it's all about "just good clean fun" and creating product awareness for 501 jeans. EVB's creative team also sees no damage in unbuttoning your beast. "We can't control what people think," said Harwell. "We created cute and fun characters that are absurd coming out of a pair of pants. The pants serve as a curtain. It's all pretty harmless."

The effort will run for at least another six months, per EVB. Levi spent $70 million on advertising in 2007, and $19 million though July of this year, per Nielsen Monitor-Plus. The lead agency for Levi is BBH, New York.