SAN JOSE (CBS SF) — The Bay Area man who invented the Pet Rock, a collectible that became a short-lived fad in the mid-1970s, died this week at the age of 78.

The toys were the creation of Gary Dahl, a copywriter from Los Gatos. Dahl died in Oregon, following a series of health problems.

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Dahl said he got the idea while listening to friends who complained about their pets. By marketing the rocks as a pet that needed no care, they became all the rage in 1975.

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Gary Dahl

Gary Dahl, inventor of the Pet Rock died in Oregon. (CBS)

“The pet rock was out from September to December. After December, it kind of dried out. But he sold four million of them,” Chris Nunez, Dahl’s daughter, told KPIX 5.

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It cost Dahl about $1 each to make the Pet Rocks and sold them for $4 apiece. He used some of the money to fulfill a dream of opening up a bar.