Apart from mood rings and All In the Family, nothing quite evokes the mid-1970s like The Pet Rock — a stroke of marketing genius from advertising copywriter Gary Dahl that went on to become a fad of national proportions, for at least a few months. Dahl, who was living in Los Gatos, California, south of San Francisco, at the time of his "invention," capitalized on the self-indulgence of the era and the country's growing taste for irony when he came up with the concept, which by the height of its fad-dom in 1975 had sold over 1.5 million units and made Dahl an instant millionaire. Dahl died at his home in Oregon last week at the age of 78 of heart disease, as the New York Times reports.

As the story goes...

One night in the mid-’70s, he was having a drink in Los Gatos, the Northern California town where he lived for many years. At the time, he was a freelance copywriter (“that’s another word for being broke,” he later said), living in a small cabin as a self-described “quasi dropout.”
The bar talk turned to pets, and to the onus of feeding, walking and cleaning up after them.
His pet, Mr. Dahl announced in a flash of bibulous inspiration, caused him no such trouble. The reason?
“I have a pet rock,” he explained.
A pet rock, Mr. Dahl quickly realized, might just have legs.

After going into production, creating a branded cardboard carrying case, a nest, a leash, and a tongue-in-cheek pamphlet guiding the care and feeding of one's pet rock, Dahl's creation got near instant buzz without the aid of the internet, landing him on The Tonight Show and in multiple magazines and newspapers. Reproductions of the rocks can still be purchased online.

With the proceeds from Pet Rock sales, Dahl decided to open a bar of his own in Los Gatos, Carry Nation's — named for the famous pre-Prohibition-era anti-liquor radical — which is still there.

Dahl returned to advertising after a couple of less successful attempts at creating gag gifts — including "Red China Dirt," which per Wikipedia was "ostensibly a plan to smuggle mainland China into the US, one cubic centimeter at a time." — and he ended up authoring Advertising for Dummies in 2000, and its subsequent editions.

Dahl and his third wife Marguerite were also sailors who loved San Francisco Bay, and Marguerite told the San Jose Mercury-News that she plans to scatter his ashes there next month.