According to a complaint filed April 11, Gerard Dogge, known professionally as Gerard Bakardy, posted a video on Google Inc's YouTube in which he performed the trick, which he called "The Rose & Her Shadow."

At the end of the video, Dogge offered to sell the trick, and threatened to place print advertisements offering to sell it for $3,050, the complaint said.

Teller said he became aware of the video on March 15 and directed YouTube to remove it. One week later, he phoned Dogge and asked him to stop marketing the work, even offering to pay for it "as it could be more efficient than filing a lawsuit."

But Dogge "countered with a much higher sum," and threatened to sell the secret if Teller did not "come to terms soon," according to the complaint.

Dogge did not immediately respond for comment.

The lawsuit was filed in the federal court in Las Vegas, where Penn & Teller regularly perform. It seeks a permanent halt to any copyright infringement, plus damages. Teller's lawyers did not immediately respond to requests for comment.

"Shadows" is "the oldest, most venerated piece of material in Penn & Teller's show," and has been performed thousands of times, according to the complaint.

It involves a spotlight shown on a vase containing a rose, with the shadow of a rose projected onto a white screen. Teller then uses a knife to sever leaves and petals of the shadow, whereupon the corresponding leaves and petals on the rose in the vase fall to the ground.

According to a certificate of copyright registration filed with the complaint, the illusion was copyrighted in 1983 by Teller, a pseudonym for Raymond Teller.

"This gothic pantomime has been performed by its creator over 1,100 times since 1976," the January 1983 certificate shows. "It's about time he registered a copyright, don't you think?"

(Reporting By Jonathan Stempel in New York; editing by John Wallace)

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