Gary Ross Dahl, the creator of the wildly popular 1970s fad the Pet Rock, has died at age 78 in southern Oregon.

Dahl's wife, Marguerite Dahl, confirmed Tuesday that her husband of 40 years died March 23 of chronic obstructive pulmonary disease.

The smooth stones came packed in a cardboard box containing a tongue-in-cheek instruction pamphlet for "care and feeding." Dahl estimated he had sold 1.5 million of them at roughly $4 each by the time the fad fizzled. The Pet Rock required no work and no time commitment.

Born Dec. 18, 1936, in Bottineau, North Dakota, Dahl was raised in Spokane, Washington.

In 1975, he was a Los Gatos, California, advertising executive when he came up with the Pet Rock idea.

Dahl also penned "Advertising for Dummies."

In 2000, he was a grand prize winner in the Bulwer-Lytton Fiction Contest for dreadful prose. His winning entry: "The heather-encrusted Headlands, veiled in fog as thick as smoke in a crowded pub, hunched precariously over the moors, their rocky elbows slipping off land's end, their bulbous, craggy noses thrust into the thick foam of the North Sea like bearded old men falling asleep in their pints. "

He and his wife retired and moved to Jacksonville in 2006.

The Pet Rock craze "was great fun when it happened," his wife recalled in a telephone interview. Over time, however, "people would come to him with weird ideas, expecting him to do for them what he had done for himself. And a lot of times they were really, really stupid ideas."

By 1988, Dahl told The Associated Press he had avoided interviews for years because of what he called "a bunch of wackos" appearing out of nowhere with threats and lawsuits.

Of the little rock that became a household word, he said, "Sometimes I look back and wonder if my life wouldn't have been simpler if I hadn't done it."

Dahl designed and built the Carry Nations Saloon in Los Gatos, his wife said.

In addition to his wife, he is survived by a sister, Candace Dahl of Spokane; daughters Chris Nunez and Samantha Leighton; son Eric Dahl; stepdaughter Vicki Pershing and grandchildren.

Dahl and his wife were avid sailors on San Francisco Bay, where she plans to sprinkle his ashes in May.